oversight

Drinking Water: Information on the Quality of Water Found at Community Water Systems and Private Wells

Published by the Government Accountability Office on 1997-06-12.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

                  United States General Accounting Office

GAO               Report to Congressional Requesters




June 1997
                  DRINKING WATER
                  Information on the
                  Quality of Water Found
                  at Community Water
                  Systems and Private
                  Wells




GAO/RCED-97-123
      United States
GAO   General Accounting Office
      Washington, D.C. 20548

      Resources, Community, and
      Economic Development Division

      B-276974

      June 12, 1997

      The Honorable J. Dennis Hastert
      The Honorable Bill Paxon
      House of Representatives

      As requested, this report provides information on (1) what is known about the quality of
      drinking water from community water systems and private wells in six states and (2) what
      factors influence the quality of drinking water from these sources. The report contains a
      recommendation designed to help ensure that owners of private wells are better informed of
      potential contamination problems whenever groundwater-based community systems detect
      contamination that may also be present at nearby private wells.

      As arranged with your offices, unless you publicly announce its contents earlier, we will make
      no further distribution of this report until 30 days after the date of this letter. At that time, we
      will send copies to the appropriate congressional committees; the Administrator,
      Environmental Protection Agency; and the Director, Office of Management and Budget. We will
      also make copies available to other interested parties upon request. Major contributors to this
      report are listed in appendix III.




      Stanley Czerwinski
      Associate Director, Environmental
        Protection Issues
Executive Summary


             The vast majority of U.S. households get their drinking water from
Purpose      community water systems regulated under the federal Safe Drinking Water
             Act. These water systems must comply with a variety of federal and state
             requirements relating to their construction, the periodic monitoring of
             their water quality, inspections, and other matters. The remaining
             households do not have access to community water systems and rely
             primarily on private domestic wells that are not subject to the act but may
             be subject to state and local requirements.

             To learn more about the quality of drinking water, Representatives J.
             Dennis Hastert and Bill Paxon and former Representative Blanche
             Lambert-Lincoln asked GAO to provide them with information on (1) what
             is known about the quality of drinking water from community water
             systems and private wells and (2) what factors influence the quality of
             drinking water from these sources. To meet these objectives, GAO gathered
             data from six states selected on the basis of such factors as the number or
             percentage of households that use private wells and the amount of
             information available on water quality from private wells. The states are
             California, Illinois, Nebraska, New Hampshire, North Carolina, and
             Wisconsin.


             The Safe Drinking Water Act, enacted in 1974, requires the Environmental
Background   Protection Agency (EPA) to establish drinking water standards for the
             nation’s nearly 56,000 community water systems. The act also requires
             water systems to monitor the water delivered to consumers to determine
             whether it meets the standards. EPA generally grants to the states the
             responsibility for enforcing these standards and for overseeing community
             water systems. In both 1986 and 1996, the Congress amended the act to
             revise the standard-setting process; strengthen enforcement authority;
             and/or add other requirements for EPA, the states, and water systems.

             An estimated 15 million households that are not served by community
             water systems get their drinking water from private, domestic wells.
             Although private wells are not covered by the Safe Drinking Water Act,
             state and local governments may establish their own requirements for
             constructing, testing, inspecting, and otherwise regulating these wells.
             Other federal and state laws’ provisions are designed to protect
             groundwater and/or surface water from contamination. Both private wells,
             which are generally supplied by groundwater, and community water
             systems, which are supplied by either groundwater or surface water, may
             be affected by these laws.



             Page 2                                   GAO/RCED-97-123 Drinking Water Quality
                            Executive Summary




                            Much more is known about the quality of drinking water from community
Results in Brief            water systems than from private wells. To meet the Safe Drinking Water
                            Act’s requirements, community water systems must periodically monitor
                            their water for contaminants, such as total coliform bacteria, pesticides,
                            naturally occurring elements, and industrial solvents. In the six states that
                            GAO reviewed, compliance data for fiscal years 1993 through 1996 show
                            that violations of the standard for total coliform bacteria were the most
                            common, being reported by 3 to 6 percent of the more than 17,000
                            community water systems. A sizable number of systems (although a small
                            percentage of the total) violated standards for radiological contaminants,
                            nitrate, and the herbicide atrazine. Violations of other standards were few.

                            For private wells, the available data on water quality are, for the most part,
                            limited to data on total coliform bacteria and nitrate. These data have been
                            collected for special studies, in response to state and local testing
                            requirements for new wells, and through voluntary testing requested by
                            well owners. While these data are not always representative or unbiased,
                            those that are have shown rates of bacterial contamination as high as
                            42 percent and rates of excessive nitrate as high as 18 percent. Less
                            extensive data on two commonly used herbicides show much lower levels
                            of contamination in private wells.

                            Several factors influence the quality of drinking water obtained from
                            community water systems and private wells. These factors include (1) the
                            condition of the source from which the drinking water is extracted; (2) the
                            use of construction standards and other controls designed to ensure that
                            new water systems and private wells are properly constructed and
                            protected from potential sources of contamination; and (3) ongoing
                            oversight and maintenance activities, such as periodic testing and
                            inspections, that help determine whether the water will continue to be
                            safe.



Principal Findings

Data on Contamination Are   Under the Safe Drinking Water Act, community water systems are required
Extensive for Community     to monitor their water for up to 72 specific contaminants, including
Water Systems and Limited   bacteria, pesticides, industrial solvents, and other chemical and
                            radiological compounds. The frequency of the required monitoring ranges
for Private Wells           from daily to once every 9 years, depending on the type of contaminant,




                            Page 3                                    GAO/RCED-97-123 Drinking Water Quality
Executive Summary




the population served by the water system, the source of the water, and
the presence of contaminants in past samples. Community water systems
may also have to employ treatment techniques to prevent unsafe levels of
up to nine other contaminants.

Four of the six states reviewed by GAO do not require any testing at private
wells; the other two states require testing for bacteria, and one of these
states requires testing for nitrate before new wells are put into service. In
some instances, local governments and lending institutions require limited
testing at new wells. Other data on the quality of private well water are
available because testing was initiated by well owners or special studies
were conducted.

In total, community water systems in the six states reviewed by GAO
exceeded the standard at least once for 25 of the regulated contaminants
during fiscal years 1993 through 1996. By far the most common problem
was contamination with total coliform bacteria, from a low of 577 systems
(3.3 percent of 17,443) reporting at least one violation in 1996 to a high of
1,035 (5.7 percent of 17,976) doing the same in 1993. The next most
common problem was exceeding the standard for naturally occurring
combined radium; an average of 129 systems (no more than 0.8 percent
per year) reported such violations over the 4 years. Other standards
violated by a number of systems over the 4 years were for nitrate (58
systems per year, on average), naturally occurring alpha emitters (53
systems, on average), and the herbicide atrazine (22 systems, on average).
Few community water systems reported violations for the other 20
contaminants.

Because water quality is not routinely monitored at private wells as it is at
community water systems, the data available for private wells are limited.
Through both representative and unrepresentative methods, such data
have been gathered for special studies, tests required by state and local
governments, and voluntary tests requested by well owners. In the six
states reviewed by GAO, the available data were primarily for total coliform
bacteria and nitrate, and only limited data existed for pesticides, heavy
metals, and volatile organic compounds. Nearly all of the data show that
contamination with total coliform bacteria is common for private wells,
that excessive nitrate concentrations range from common to rare, and that
contamination with herbicides is rare, as shown by the following. A 1994
survey led by the Centers for Disease Control and Prevention (CDC)
collected data on total coliform bacteria and nitrate concentrations from a
sample of geographically distributed private wells in three of the six states



Page 4                                    GAO/RCED-97-123 Drinking Water Quality
                          Executive Summary




                          included in GAO’s study. Total coliform bacteria in excess of the standard
                          were detected in 46, 37, and 23 percent of the wells tested in Illinois,
                          Nebraska, and Wisconsin, respectively. Nitrate was detected in
                          concentrations exceeding EPA’s standard in 15, 15, and 7 percent of the
                          wells tested in the three states, respectively. The study reported the
                          herbicide atrazine at levels above EPA’s standard at no more than
                          0.2 percent of the wells in these three states.

                          Community water systems and private wells located in the same general
                          area may use the same source of groundwater. Thus, according to EPA and
                          state drinking water officials, some of the contaminants detected in
                          community systems are likely to be present in nearby private wells. This is
                          most likely to be true for contaminants, such as nitrate and various
                          pesticides, that have leached into the groundwater after long-term
                          application on the land. However, community water systems are required
                          to treat their water when necessary or to take other actions to avoid
                          violating water quality standards.

                          In 1975, under authority of the Safe Drinking Water Act, EPA began
                          requiring community water system owners to inform their customers
                          whenever their systems exceed the standard for a regulated contaminant.
                          The 1996 amendments require that after August 1998, community water
                          system owners annually inform their customers of all detections of
                          contaminants. Water quality data from testing community water systems
                          that use groundwater may be useful to private well users if they derive
                          groundwater from the same source, particularly because private well users
                          rarely test their water for most contaminants regulated by the act.
                          However, community water system owners are required to notify only
                          their customers and not private well users whenever contamination is
                          detected in groundwater. Hence, private well users may not be aware of
                          nearby contamination that could affect their water supply.


Condition of Source,      The condition of the water source can significantly affect the quality of
Standards for Well        drinking water supplied by community water systems and private wells,
Construction, and Other   particularly if the water is untreated. Community systems are much more
                          likely than private well users to treat their water for contaminants that
Factors Influence Water   pose health risks. In addition, private wells are typically shallower than the
Quality                   wells in community systems and are more likely to tap into contamination
                          that has leached into groundwater from the surface.




                          Page 5                                    GAO/RCED-97-123 Drinking Water Quality
                 Executive Summary




                 Another key factor influencing water quality is the nature of the controls
                 in place to help ensure that new drinking water sources, including both
                 community systems and private wells, are properly constructed and
                 protected from potential contamination. All six of the states reviewed by
                 GAO have established construction standards and siting requirements that
                 specify minimum distances between the water source and potential
                 sources of contamination for both community water systems and private
                 wells. As regulated public water supplies, new or substantially modified
                 community systems must undergo a rigorous approval process. However,
                 states and local communities vary in the extent to which they impose
                 controls over new private wells.

                 Ongoing oversight and maintenance activities, such as the periodic
                 monitoring of water quality and routine inspections—and the extent to
                 which such activities trigger corrective action—also influence water
                 quality. As noted earlier, community water systems are subject to
                 extensive testing, and states periodically conduct comprehensive
                 inspections of water systems’ design, operation, and maintenance.
                 However, the primary responsibility for the ongoing oversight and
                 maintenance of private wells rests with individual homeowners; none of
                 the states GAO visited requires testing at existing wells or conducts routine
                 inspections. For example, because of financial constraints, New
                 Hampshire officials have inspected only four or five of the estimated
                 50,000 private wells constructed over the past 12 years. When
                 contamination is detected at community systems, states can compel
                 corrective action. But identifying and correcting contamination problems
                 at private wells is generally left to the discretion of the well owners.


                 To help ensure that private well users are better informed of potential
Recommendation   contamination problems and associated health risks, GAO recommends that
                 the Administrator, Environmental Protection Agency, explore options that
                 would provide such well users with information on how to learn more
                 about the quality of their drinking water and the steps they can take to
                 protect the source of their drinking water from contamination. For
                 example, state and/or local health agencies could use the local media to
                 alert private well users to consider testing their water whenever the
                 testing of a groundwater-supplied community water system detects
                 contamination that could potentially be present in the same geologic
                 formation supplying nearby private wells.




                 Page 6                                    GAO/RCED-97-123 Drinking Water Quality
                  Executive Summary




                  GAO provided a draft of this report to EPA, CDC, and the six states that GAO
Agency Comments   reviewed. GAO obtained comments from EPA officials, including the
                  Director of the Implementation and Assistance Division of the Office of
                  Ground Water and Drinking Water, and CDC officials from the National
                  Center for Environmental Health and the National Center for Infectious
                  Diseases. GAO also obtained comments from representatives of the state
                  agencies responsible for overseeing drinking water quality. The federal
                  agencies and states generally agreed with the information presented in the
                  report. They did offer updated information or technical comments, which
                  GAO incorporated throughout the report, as appropriate. EPA, CDC, and the
                  states agreed with the intent of GAO’s recommendation and offered
                  suggestions for clarifying and expanding it. GAO has revised the
                  recommendation to give EPA and the states more flexibility in achieving the
                  goal of increasing the amount of water quality information available to
                  private well users.




                  Page 7                                   GAO/RCED-97-123 Drinking Water Quality
Contents



Executive Summary                                                                                  2


Chapter 1                                                                                         10
                        Most Americans Get Their Drinking Water From Community                    10
Introduction              Water Systems or Private Wells
                        Sources of Drinking Water Are Vulnerable to Contamination                 11
                        EPA Regulates Community Water Systems and Sets Standards for              12
                          the Quality of Drinking Water
                        State and Local Governments Set Requirements for Private Wells            14
                        Other Federal, State, and Local Programs May Protect Sources of           14
                          Drinking Water
                        Objectives, Scope, and Methodology                                        14

Chapter 2                                                                                         17
                        Compared With Private Wells, Community Systems Must Comply                18
Data on Total             With Extensive Testing Requirements
Coliform Bacteria,      Bacterial Contamination Is the Most Common Problem at                     21
                          Community Water Systems in the Six States
Nitrate, and Other      Limited Test Data on Private Wells Indicate Frequent                      22
Contaminants at           Contamination From Bacteria and Nitrate
Community Systems       Data on Private Wells for Other Contaminants Are Very Limited             27
                          and Show Low Rates of Excessive Contamination
and Private Wells       Contaminated Groundwater May Affect Both Community Water                  28
                          Systems and Private Wells
                        SDWA’s Requirement for Expanded Public Notification Could                 29
                          Benefit Private Well Users
                        Conclusions                                                               29
                        Recommendation                                                            30
                        Agency Comments                                                           30

Chapter 3                                                                                         32
                        The Condition of the Source Influences Drinking Water Quality             32
Several Factors         Construction Standards, Siting Requirements, and Other Controls           33
Influence the Quality     Help Reduce Potential for Contamination
                        Ongoing Oversight and Maintenance Help Ensure That Existing               39
of Drinking Water         Sources of Drinking Water Continue to Provide Good-Quality
From Community            Water
Water Systems and
Private Wells



                        Page 8                                 GAO/RCED-97-123 Drinking Water Quality
             Contents




Appendixes   Appendix I: Description of Common Well Construction Methods                44
             Appendix II: Data on Contamination by Total Coliform Bacteria              45
               and Nitrate at Private Wells
             Appendix III: Major Contributors to This Report                            47

Tables       Table 2.1: Years Elapsed Since Last Water Test Was Conducted               20
               for Private Well Owners Participating in University of Wisconsin’s
               1985-96 Testing Program
             Table 2.2: Number and Percentage of Community Water Systems                22
               in Six States With at Least One Water Quality Violation in Fiscal
               Years 1993-96 for the Most Frequently Exceeded Standards
             Table 2.3: Results of CDC’s Survey of the Presence of                      24
               Contaminants in Water From Private Wells in Nine Midwestern
               States
             Table 2.4: Summary of Total Coliform and Nitrate Results from              25
               Other Studies Using Statistically Representative Methodologies
             Table II.1: Data on Contamination by Total Coliform Bacteria at            45
               Private Wells
             Table II.2: Data on Contamination by Nitrate at Private Wells              46




             Abbreviations

             CDC        Centers for Disease Control and Prevention
             EPA        Environmental Protection Agency
             GAO        General Accounting Office
             MCL        maximum contaminant level
             SDWA       Safe Drinking Water Act


             Page 9                                  GAO/RCED-97-123 Drinking Water Quality
Chapter 1

Introduction


                       Because safe drinking water is essential to public health, the quality of the
                       nation’s drinking water supply is an issue of national importance. For the
                       most part, consumers receive drinking water from either community water
                       systems or private wells. The water, which may be tapped from
                       groundwater aquifers or surface water bodies, is vulnerable to a wide
                       range of pollutants from agricultural, industrial, urban, and residential
                       land uses, as well as natural causes. In response to these threats, federal,
                       state, and local governments have put regulatory programs in place to
                       prevent consumers from drinking contaminated water. However,
                       variations in the sources of drinking water, in its delivery to consumers,
                       and in the extent to which its quality is regulated have raised questions
                       about whether safe drinking water is being consistently delivered to all
                       citizens.


                       The vast majority of Americans get their residential drinking water from
Most Americans Get     one of two categories of delivery systems—community water systems or
Their Drinking Water   private wells. According to the 1990 census, about 84 percent of the
From Community         nation’s 102 million households obtained their drinking water from
                       community water systems, most of which are regulated under the Safe
Water Systems or       Drinking Water Act (SDWA) of 1974.1 Of the remaining 16 percent of
Private Wells          households, about 15 million received their drinking water from private
                       wells and about 1 million used small unregulated water systems.2 Private
                       wells are not regulated under SDWA but may be regulated by state and local
                       governments. Other means of drinking water delivery include
                       SDWA-regulated noncommunity systems.3


                       About 55,600 community water systems operated in the United States in
                       fiscal year 1995, compared with over 59,000 in fiscal year 1991. This
                       decline is attributed, at least in part, to the consolidation of small systems
                       into larger ones. Despite this trend toward consolidation, about 85 percent
                       of the community systems are small, serving fewer than 3,300 people.

                       1
                        The U.S. Bureau of the Census defines a community water system as one that supplies water to five or
                       more housing units. This definition contrasts with SDWA’s, under which a community water system is
                       one that serves at least 25 year-round residents or has at least 15 year-round service connections.
                       2
                        A water system that has fewer than 15 service connections or serves fewer than 25 people is not
                       regulated under SDWA. Such a system may be regulated by a state or local government. An estimated
                       1 percent of the population is served by this type of system.
                       3
                        Under SDWA, noncommunity water systems are divided into two categories: transient and
                       nontransient noncommunity systems. Transient noncommunity systems serve at least 25 people for
                       more than 60 days a year but do not regularly serve any given 25 people for more than 6 months a year.
                       Examples include gas stations and roadside rest areas. Nontransient noncommunity systems regularly
                       serve at least 25 of the same people for more than 6 months a year. Examples of these systems are
                       schools, factories, or office buildings.



                       Page 10                                                GAO/RCED-97-123 Drinking Water Quality
                       Chapter 1
                       Introduction




                       The National Ground Water Association estimates that over 300,000 new
                       private wells are drilled each year. There are several reasons why many
                       Americans obtain their drinking water from private wells. Many live in
                       sparsely populated rural areas where it is not economically feasible to
                       install community water systems. Some consumers have put in private
                       wells to avoid the increasing cost of the water supplied by community
                       systems, and others simply prefer to control their own water source.

                       Most Americans also drink water outside the home, such as at work,
                       school, and restaurants and while traveling. The source of this water may
                       be a community water system, a private well, or what is known under SDWA
                       as a noncommunity system. While noncommunity systems do not serve
                       residential customers, they must still meet certain requirements for their
                       operation, water quality monitoring, and water treatment. The focus of this
                       report is on water consumed in the home from private wells and regulated
                       community systems. In this report, the term private well includes the well,
                       the pump, and the connections leading to the household tap.


                       Drinking water delivered by community systems and private wells comes
Sources of Drinking    from two sources: surface water and groundwater. Both sources are
Water Are Vulnerable   vulnerable to contamination. Surface water is drawn from rivers, lakes,
to Contamination       streams, and reservoirs. Groundwater is pumped by wells from porous
                       rock, sand, or gravel saturated with water that has percolated down from
                       the surface. Community water systems may rely on groundwater, surface
                       water, or both, while private wells generally rely on groundwater.
                       Groundwater and surface water each supply about 50 percent of the
                       country’s drinking water.

                       The quality of the water source can be affected by a variety of factors,
                       including local land uses, the local geology, and—for groundwater—the
                       depth of the aquifer from which the water is extracted. Groundwater is
                       vulnerable to contaminants that filter down into underground aquifers
                       from the surface; when this occurs, the water level closest to the surface is
                       affected first. Deeper levels of an aquifer or areas that are protected by a
                       confining clay layer are often unaffected by surface contamination.
                       Surface water is vulnerable to contaminants from runoff, precipitation, air
                       pollution, and direct discharges from industrial and municipal facilities.

                       Local land uses can have a significant impact on groundwater and surface
                       water. For example, in some agricultural areas, the long-term application
                       of pesticides and fertilizers has contaminated underlying groundwater.



                       Page 11                                   GAO/RCED-97-123 Drinking Water Quality
                      Chapter 1
                      Introduction




                      Near landfills and industrial facilities, improper waste disposal or
                      chemical spills have also contaminated groundwater. And man-made
                      contaminants may be introduced into groundwater by other means. For
                      example, abandoned wells that have not been properly sealed can serve as
                      conduits for contamination from the surface. Naturally occurring
                      inorganic compounds—such as fluoride, arsenic, and various radiological
                      compounds—may also be present in groundwater, depending on the type
                      and location of geological formations. The extent and depth of the
                      contamination that leaches down from the surface can vary with the
                      volume and type of the contaminant, the permeability of the soil, the
                      amount of rainfall in the area, and other environmental characteristics.

                      Surface water has also been affected by contaminated runoff from
                      agricultural lands and urban areas. Regions that experience greater rainfall
                      or are prone to flooding are more vulnerable to contamination from runoff
                      than more arid regions. Other potential sources of surface water
                      contamination include chemical discharges from industrial and municipal
                      wastewater treatment facilities and the atmospheric deposition of heavy
                      metals and other substances contained in emissions from manufacturing
                      plants and other facilities.

                      Drinking water contamination can also occur within the distribution
                      system. For both private wells and community water systems, this system
                      includes the connections between the well or treatment facility and the
                      household tap. For example, a breach in the distribution system could
                      allow bacteria to contaminate drinking water.


                      With the enactment of SDWA in 1974, the Congress established a national
EPA Regulates         program to ensure that all community water systems meet minimum
Community Water       standards to protect public health. SDWA directed the Environmental
Systems and Sets      Protection Agency (EPA) to establish (1) national drinking water standards
                      or treatment techniques for contaminants that could adversely affect
Standards for the     public health and (2) requirements for monitoring the quality of drinking
Quality of Drinking   water and for ensuring the proper operation and maintenance of water
                      systems. SDWA also authorizes EPA to grant primary enforcement authority
Water                 for the drinking water program, commonly referred to as “primacy,” to
                      states that meet certain requirements. With EPA’s oversight, the states with
                      primacy enforce the drinking water program’s requirements and oversee
                      the public water systems within their jurisdiction. The states maintain
                      other oversight activities to ensure that public water systems meet design,
                      construction, and water quality standards.



                      Page 12                                  GAO/RCED-97-123 Drinking Water Quality
Chapter 1
Introduction




For each of the currently regulated contaminants,4 EPA was required under
SDWA to establish (1) a health-based goal at a level at which no known or
anticipated adverse health effects occur and that allows an adequate
margin of safety and (2) a national primary drinking water regulation,
generally based on the highest allowable concentration of a contaminant
in drinking water, called a maximum contaminant level (MCL). SDWA
required EPA to set the MCL as close to the health-based goal as feasible,
considering the available technology and costs.5 EPA was allowed to
specify a treatment technique in lieu of an MCL whenever it was not
feasible to measure the level of a contaminant in drinking water.6 EPA’s
responsibilities in setting standards for the quality of drinking water were
recently modified under the 1996 amendments to SDWA. The agency now
has more flexibility in deciding which contaminants should be regulated
and may give greater consideration to relative costs and risk-reduction
benefits.

EPA currently regulates 81 contaminants that could adversely affect public
health7 and has established MCLs for 72 of these contaminants. Community
water systems are required to test their water for the 72 contaminants and
take certain corrective actions if they find levels above an MCL. For the
remaining nine contaminants, EPA requires that community systems use
specific treatment techniques that will reduce contaminants to acceptable
levels. Additional monitoring may be required in conjunction with the use
of these treatment techniques. EPA also sets “secondary” standards for
contaminants that affect the aesthetic quality of drinking water, such as its
taste, odor, and appearance. While the presence of these contaminants
may be unpleasant, EPA does not consider them to be unhealthy. Both
community water systems and private wells may be affected by the
presence of secondary contaminants, and both systems have treatment
options that may improve their water.



4
 The contaminants currently regulated under EPA’s safe drinking water program include various
inorganic, volatile organic, and synthetic organic chemicals; radioactive chemicals; and
microbiological contaminants.
5
 On the basis of the legislative history, EPA decides, when considering costs, whether the technology
is reasonably affordable to regional and large metropolitan water systems.
6
 For some contaminants, the available analytical methods are not economically or technologically
feasible; that is, the methods are too costly or are not sufficiently accurate or reliable. For these
contaminants, EPA identifies treatments that are effective in reducing risks.
7
 EPA has set standards for three other contaminants (aldicarb, aldicarb sulfone, and aldicarb
sulfoxide) but is reconsidering these standards in light of new evidence and has delayed their
implementation.



Page 13                                                  GAO/RCED-97-123 Drinking Water Quality
                        Chapter 1
                        Introduction




                        Although private wells are not regulated under SDWA, they are subject to
State and Local         state and local regulations. For example, state and local governments may
Governments Set         issue permits for, require testing of, or conduct inspections at private
Requirements for        wells. The degree to which state and local governments have acted to
                        regulate private wells varies from state to state.
Private Wells
                        One area of state regulation concerns the construction of private wells.
                        Over time, different types of wells have been developed to meet specific
                        geological conditions and to reflect advances in technology. Not all
                        construction methods are now considered acceptable, and state
                        requirements can be very specific. (See app. I for a brief description of
                        common construction methods for wells.)

                        State and local oversight of private wells not only provides some degree of
                        consumer protection to well users but also helps protect the nation’s
                        groundwater resources. Inadequately constructed or improperly
                        abandoned wells can serve as conduits for contamination from the surface
                        to enter the groundwater.


                        In addition to the federal, state, and local programs that specifically
Other Federal, State,   address community and private drinking water delivery systems, other
and Local Programs      programs are in place to protect source waters from contamination. Some
May Protect Sources     of these programs are implemented by the states under the authority of
                        federal statutes, while others exist at the states’ discretion. Such programs
of Drinking Water       include, for example, groundwater protection standards and monitoring;
                        wellhead protection and underground injection control programs under
                        SDWA; controls over facilities that treat, store, and dispose of hazardous
                        waste under the Resource Conservation and Recovery Act; statewide
                        septic system and pesticide management regulations; well abandonment
                        standards; and controls over chemical discharges from industrial and
                        municipal wastewater treatment plants under the Clean Water Act. Other
                        programs are targeted at more diffuse, or “nonpoint,” sources of pollution,
                        such as agricultural and urban runoff.


                        At the request of Representatives J. Dennis Hastert and Bill Paxon and
Objectives, Scope,      former Representative Blanche Lambert-Lincoln, we reviewed the quality
and Methodology         of drinking water in community water systems and private wells. In
                        discussions with the requesters’ offices, we agreed to provide information
                        in response to the following questions:




                        Page 14                                   GAO/RCED-97-123 Drinking Water Quality
    Chapter 1
    Introduction




•   What is known about the quality of drinking water from community water
    systems and private wells in six states?
•   What factors influence the quality of drinking water from community
    water systems and private wells?

    In conducting this review, we collected information from a wide variety of
    sources, including EPA, the U.S. Geological Survey, the U.S. Public Health
    Service’s Centers for Disease Control and Prevention (CDC), the U.S.
    Department of Agriculture, the Bureau of the Census, selected states, and
    other relevant organizations. We judgmentally selected six states for our
    review—California, Illinois, Nebraska, New Hampshire, North Carolina,
    and Wisconsin. These states were selected on the basis of several factors,
    including (1) the amount of information available on private wells located
    in the states as identified in interviews with knowledgeable officials,
    (2) the number or percentage of households that obtain their drinking
    water from private wells, and (3) the states’ geographical location.

    To answer the first question, we obtained data from EPA on contaminants
    found in community water systems in the six states for fiscal years 1993
    through 1996. We identified and obtained data on contaminants found in
    private wells through interviews with drinking water officials responsible
    for overseeing private wells in each state. We also identified and obtained
    water quality studies done by researchers in academia, industry, or
    government who analyzed private wells in any of the six states as well as
    other states. We interviewed federal, state, and local agency officials to
    discuss the testing data available on community water systems and private
    wells. We used EPA’s primary drinking water standards—the MCLs that EPA
    has established to protect public health—as our criteria for assessing
    water quality at private wells.

    To answer the second question, we interviewed federal, state, and local
    government officials; representatives from the National Ground Water
    Association; representatives of the state well drillers’ association within
    each of the six states; and water quality experts from academia. We
    reviewed the federal and state regulations for community water systems.
    For private wells, we obtained state and local regulations on the
    construction and location of wells, as well as operating and licensing
    requirements for well drillers. We also collected and reviewed public
    educational literature designed for private well users.

    We provided a draft of this report to EPA, CDC, and the six states for their
    review. Specifically, we obtained comments from EPA officials, including



    Page 15                                   GAO/RCED-97-123 Drinking Water Quality
Chapter 1
Introduction




the Director of the Implementation and Assistance Division of the Office
of Ground Water and Drinking Water, and CDC officials from the National
Center for Environmental Health and the National Center for Infectious
Diseases. We also obtained comments from representatives of the state
agencies responsible for overseeing drinking water quality. We responded
to their comments throughout the report and summarized their views in
the executive summary and chapter 2.

Our work was conducted from July 1996 through April 1997 in accordance
with generally accepted government auditing standards.




Page 16                                GAO/RCED-97-123 Drinking Water Quality
Chapter 2

Data on Total Coliform Bacteria, Nitrate,
and Other Contaminants at Community
Systems and Private Wells
               Much more is known about the quality of drinking water from community
               water systems than from private wells because community water systems
               are tested much more extensively. Under SDWA, community water systems
               must routinely test their water for the presence of up to 72 contaminants.8
               Private wells are not subject to SDWA, and none of the six states we
               reviewed requires any routine testing of operating wells. Two of the six
               states and some local governments require minimal testing at new private
               wells before they are put into operation.

               Extensive data from community water systems in the six states that we
               reviewed showed that total coliform bacteria9 were the most common
               contamination problem. Between 3 and 6 percent of the community
               systems operating in the six states between fiscal years 1993 and 1996
               exceeded the MCL for total coliform bacteria.10 Relatively few community
               systems exceeded other MCLs. The next most frequently exceeded standard
               was for combined radium, with fewer than 1 percent of the systems
               exceeding that standard in any one year.11

               Most of the data that we found on the quality of private well water are for
               total coliform bacteria and nitrate.12 The data—which come from a variety
               of states, including the six we reviewed in detail—indicate that a high
               percentage of private wells were contaminated with total coliform bacteria



               8
                EPA requires that community water systems have treatment techniques in place to reduce the
               presence of nine additional contaminants that are not economically or technologically feasible to
               detect through testing. Additional monitoring may be required together with the use of the treatment
               techniques.
               9
                Total coliform bacteria are microscopic, generally harmless, organisms that live in the intestinal tracts
               of warm-blooded animals. According to EPA, the presence of total coliform bacteria indicates the
               possible presence of fecal and disease-causing bacteria.
               10
                 The MCL for total coliform bacteria that community systems must meet is based on the presence or
               absence of coliform bacteria in a percentage of all samples taken each month. The number of samples
               taken depends on the size of the population served. The MCL is exceeded when systems that take
               fewer than 40 samples per month detect total coliform bacteria in more than 1 sample or when
               systems that take 40 or more samples detect the bacteria in more than 5 percent of the samples. The
               MCL is also exceeded if any fecal coliform bacteria or E. coli are detected.
               11
                Note that the community water systems’ data in this report are limited to violations of MCLs and do
               not include violations of monitoring requirements. It is possible that monitoring violations could
               obscure violations of water quality standards.
               12
                 The sources of nitrate in drinking water include fertilizers, animal waste, the contents of septic tanks,
               and decaying plant material. Nitrate levels below 3 parts per million are considered background levels,
               and higher levels are considered to be caused by human activity. EPA’s MCL for nitrate in drinking
               water is 10 parts per million. Infants are particularly susceptible to high nitrate levels and may develop
               methemoglobinemia (also known as “blue baby syndrome”), a potentially fatal condition that restricts
               the movement of oxygen through the bloodstream.



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                    Chapter 2
                    Data on Total Coliform Bacteria, Nitrate,
                    and Other Contaminants at Community
                    Systems and Private Wells




                    and a lower percentage contained excessive nitrate concentrations.13 For
                    example, studies have reported contamination with total coliform bacteria
                    in 15 to 42 percent of the private wells tested and excessive nitrate
                    concentrations in 2 to 18 percent of the private wells. In contrast, fewer
                    than 1 percent of the private wells contained a particular pesticide above
                    acceptable levels, according to the studies we identified. Data from CDC,
                    EPA, and others suggest to us that contamination rates at private wells are
                    related to a number of characteristics of the wells, including their age and
                    type.

                    EPA and state officials indicated that contaminants such as pesticides
                    found in community water system wells may also be present in nearby
                    private wells that draw on the same groundwater, but private well water is
                    seldom tested for contaminants other than bacteria and nitrate. The 1996
                    amendments to SDWA require EPA to develop, by August 1998, regulations
                    that will require that community water system operators notify their
                    customers of the amount of contamination found in their drinking water.
                    However, this information will not be provided routinely to private well
                    users who may use the same source of groundwater as the community
                    system.


                    All community water systems must test their water for contaminants
Compared With       regulated by SDWA. The frequency of testing varies from one contaminant
Private Wells,      to another and ranges from more than once a day to once every 9 years.
Community Systems   Other factors that affect the frequency of testing include the size of the
                    population served by the system, the source of the water (groundwater
Must Comply With    versus surface water), and past test results. In addition, states with
Extensive Testing   primacy and approved waiver programs may grant waivers that reduce the
                    sampling frequency for a specific contaminant on the basis of previous
Requirements        sampling results and/or an assessment of the system’s vulnerability to each
                    specific contaminant.14 Community systems report their test results to the
                    states and must also notify their customers when MCLs are violated. The
                    notification may be through the local media, by mail, or by hand,
                    depending upon the nature and duration of the violation.



                    13
                     In this report, private wells are considered contaminated if total coliform bacteria are present in any
                    amount. Nitrate concentrations of more than 10 parts per million are considered excessive.
                    14
                      We reported on the states’ participation in the waiver program in November 1995 (Flexibility in the
                    Safe Drinking Water Act, GAO/RCED-96-12R). At that time, we reported that 42 states had begun
                    issuing monitoring waivers by 1995. Of the remaining eight states, three had approved programs but
                    had not issued any waivers at the time of our survey and five were still developing their waiver
                    programs.



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Chapter 2
Data on Total Coliform Bacteria, Nitrate,
and Other Contaminants at Community
Systems and Private Wells




While community water systems must test for dozens of contaminants as
part of their normal operations, testing at private wells is much more
limited, and the data are not always available for review. None of the six
states we reviewed requires any routine testing of operating wells.15 Of
these six states, two (Wisconsin and Illinois) require only that newly
constructed wells be tested for total coliform bacteria before they are put
into operation. Illinois also requires, and Wisconsin recommends, that new
wells be tested for nitrate. According to state officials, while North
Carolina does not require any testing, 22 of its 87 local health boards have
private well inspection and oversight programs and may require testing for
total coliform bacteria at new wells.16 Similarly, all 58 counties in
California have private well oversight and inspection programs and some
may require testing for bacteria at new wells. State officials were not able
to identify how many counties require testing.

According to state officials, some commercial mortgage lenders require
that private wells be tested as a condition of the loan approval. They said
that testing is typically limited to total coliform bacteria and nitrate. Well
owners may choose to have the testing done by either a private or a public
(state or county) laboratory. Officials told us that test data generated by
private laboratories are not submitted to any public agency, and therefore
the information is not captured in any state database. Several of the state
laboratories in the six states conduct testing for these real estate transfers
and do maintain the results in a public database. Federal agencies that
provide mortgage insurance, including the departments of Veterans Affairs
and Housing and Urban Development, also require testing as a condition
of providing their insurance. For example, the Department of Housing and
Urban Development, in consultation with EPA, developed a testing
requirement for total coliform bacteria, nitrate, lead, and other
contaminants of local concern.

For the most part, private wells are tested at the well owner’s discretion.
As with the testing done as part of a real estate transfer, this self-initiated
testing may be done by a private or a public laboratory. Consequently, the
data may or may not be entered into a public database. According to
officials we spoke with, private laboratories treat their data as confidential



15
 In this section, we make an important distinction between newly constructed wells, which have not
yet been placed in operation, and existing wells, which are in operation and may have been so for
many years.
16
 North Carolina has 87 local health boards that serve the state’s 100 counties. Some health boards
serve more than one county.



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                                          Data on Total Coliform Bacteria, Nitrate,
                                          and Other Contaminants at Community
                                          Systems and Private Wells




                                          and do not make them available for review. This policy limits the amount
                                          of available data on the quality of private well water.

                                          Although EPA, state drinking water officials, and industry groups
                                          recommend annual testing for bacteria, few well owners follow this
                                          advice. For example, EPA’s 1984 National Statistical Assessment of Rural
                                          Water Conditions reported that “bacteriological tests and chemical (or
                                          physical) water tests by rural residents were not common. Slightly more
                                          than one-third of all rural households with individual systems had tested
                                          the water at least once, with bacteriological tests being more frequent than
                                          chemical tests.” Data from a 1994 CDC survey of 5,520 private well users
                                          across a nine-state region show that 44 percent of the respondents said
                                          that their well had never been tested for contamination, 44 percent said
                                          that it had, and 11 percent did not know.17 Of those that knew that their
                                          well had been tested and could say when the test had occurred, 39 percent
                                          said that it was prior to 1990.

                                          In the course of testing water quality at the request of more than 32,000
                                          well owners since 1985, the University of Wisconsin asked them how
                                          recently they had tested their water. Only 9 percent of the owners reported
                                          having had a test done within the last year. The overall responses are
                                          summarized in table 2.1.

Table 2.1: Years Elapsed Since Last
Water Test Was Conducted for Private      Time frame for                 Less                                      More
Well Owners Participating in University   most recent water            than 1       1-2       2-5      5-10      than 10              Not
of Wisconsin’s 1985-96 Testing            quality test                   year     years     years     years        years     Never known
Program                                   Percent of
                                          respondents                        9         6       10          6            6         3        61
                                          Source: University of Wisconsin Cooperative Extension Service.




                                          17
                                           We obtained data from CDC that it had gathered in its survey. CDC’s report entitled A Survey of the
                                          Presence of Contaminants in Water From Private Wells in Nine Midwestern States, U.S. Public Health
                                          Service, Centers for Disease Control and Prevention, is currently under review at CDC. The states
                                          surveyed were Illinois, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota, and
                                          Wisconsin.



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                       Data on Total Coliform Bacteria, Nitrate,
                       and Other Contaminants at Community
                       Systems and Private Wells




                       Data for the six states we reviewed show that the standard for total
Bacterial              coliform bacteria was the most frequently exceeded standard at
Contamination Is the   community water systems. The number of systems exceeding the standard
Most Common            for total coliform bacteria from fiscal year 1993 through fiscal year 1996
                       ranged from 577 to 1,035. This represented about 3 to 6 percent of the
Problem at             approximately 17,000 to 18,000 community water systems operating in the
Community Water        six states at some point during these years.
Systems in the Six     The community water systems in the six states we reviewed exceeded the
States                 MCLs for contaminants other than total coliform bacteria much less often.
                       The most commonly exceeded standards, other than the standard for total
                       coliform bacteria, were those for radiological elements, nitrate, and the
                       herbicide atrazine.18 Fewer than 1 percent of the systems exceeded the
                       standard for any one of these contaminants in any particular year. While
                       the systems that reported violations varied in size and used both surface
                       water and groundwater, most served fewer than 3,301 people and most
                       relied on groundwater as their source.19 Violations of the most commonly
                       exceeded standards in the six states are analyzed in table 2.2.




                       18
                         Atrazine is an herbicide used to control grasses and broadleaf weeds, primarily on corn and sorghum
                       fields. It is known to cause mammary gland cancer in laboratory animals, and EPA classifies it as a
                       possible human carcinogen.
                       19
                         EPA categorizes community water systems as very small, small, medium, large, and very large. Very
                       small systems serve from 25 to 500 people, while small systems serve from 501 to 3,300 people. From
                       fiscal year 1993 through fiscal year 1996, 80 percent of the systems with at least one water quality
                       violation were very small or small. During that same period, 87 percent of the systems with at least one
                       water quality violation used groundwater, while 13 percent used surface water.



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                                           Data on Total Coliform Bacteria, Nitrate,
                                           and Other Contaminants at Community
                                           Systems and Private Wells




Table 2.2: Number and Percentage of Community Water Systems in Six States With at Least One Water Quality Violation in
Fiscal Years 1993-96 for the Most Frequently Exceeded Standardsa
                 Systems with at least one Systems with at least one Systems with at least one Systems with at least one
                violation of standard in FY violation of standard in FY violation of standard in FY violation of standard in FY
SDWA                1993 (No. = 17,976)         1994 (No. = 17,727)         1995 (No. = 17,580)         1996 (No. = 17,443)
contaminant              No.           Pct.              No.              Pct.              No.               Pct.               No.               Pct.
Total coliform
bacteria                1,035          5.76              785             4.43               659               3.75              577                3.31
Fecal coliform
bacteria and/or
E. colib                 229           1.27              101             0.57                 63              0.36                51               0.29
Nitrate                    72          0.40               58             0.33                 52              0.30                51               0.29
Combined
radium (radium
226 and/or
radium 228)              147           0.82              130             0.73               121               0.69              116                0.67
Atrazine                   10          0.06               28             0.16                 34              0.19                15               0.09
Alpha emitters,
excluding radon
and uranium                55          0.31               56             0.32                 53              0.30                47               0.27
Total for all
contaminantsc           1,303          7.25             1,047            5.91               906               5.15              774                4.44
                                           Legend

                                           No. = number
                                           Pct. = percent
                                           a
                                              Both surface water and groundwater systems are combined.
                                           b
                                            Violations for fecal coliform bacteria and E. coli are a subset of the violations for total coliform
                                           bacteria and represent more acute health risks to consumers.
                                           c
                                            Will not equal the total number of systems included above for two reasons: (1) a system may
                                           have a violation in several SDWA contaminant categories and (2) the total includes violations of
                                           standards for other contaminants not listed above.

                                           Source: GAO’s analysis of data from EPA.




                                           Available data on the quality of water from private wells are, for the most
Limited Test Data on                       part, limited to information on total coliform bacteria and nitrate. Whereas
Private Wells Indicate                     data on community water systems are collected using EPA’s standardized
Frequent                                   methodology, the data on private wells come from a variety of sources
                                           using various methodologies. Given that potential limitation, the data
Contamination From                         generally indicate that a high percentage of private wells were
Bacteria and Nitrate                       contaminated with total coliform bacteria at the time they were tested. A
                                           smaller percentage of private wells were contaminated with excessive



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                             Chapter 2
                             Data on Total Coliform Bacteria, Nitrate,
                             and Other Contaminants at Community
                             Systems and Private Wells




                             concentrations of nitrate. For example, CDC’s 1994 survey of the
                             geographic distribution of contamination in private wells across a
                             nine-state region found that over 41 percent of the wells were
                             contaminated with total coliform bacteria and over 13 percent contained
                             excessive concentrations of nitrate. In addition, the survey showed that
                             11 percent of the wells were contaminated with E. coli bacteria, which
                             present a more acute health risk than total coliform bacteria. Data from
                             one national and one statewide study that both used statistically random
                             sampling techniques found total coliform bacteria contamination in 42 and
                             15 percent of the private wells tested, respectively. Other data from
                             studies that used random sampling techniques showed excessive nitrate
                             concentrations at 2 to 19 percent of the private wells tested. Data gathered
                             by CDC, EPA, and others also suggested that contamination rates can be
                             affected by characteristics of a well, such as its type, depth, and age.


Specific Studies Show a      Several studies have shown a high percentage of private wells
High Percentage of Private   contaminated with total coliform bacteria and nitrate above acceptable
Wells With Contamination     levels. One of the more recent and extensive efforts was by CDC. In 1994,
                             CDC and state agencies sampled wells in nine states, including three of the
                             six that we reviewed. The purpose of the survey was to measure total
                             coliform bacteria, E. coli, nitrate, and the herbicide atrazine. The study
                             was motivated, in part, by the discovery that a high proportion of water
                             samples from rural wells were contaminated with total coliform bacteria
                             and E. coli shortly after the disastrous 1993 flooding of the Missouri and
                             Mississippi rivers. The survey was intended to show the geographic
                             distribution of microbiological and chemical contamination in water from
                             these wells.20 In total, over 5,500 wells were sampled, including more than
                             500 each in Illinois, Nebraska, and Wisconsin. The samples included wells
                             ranging in age from 1 to 200 years and wells of many different construction
                             types, including wells that would not meet the states’ current construction
                             standards. The total coliform bacteria, E. coli, and nitrate results for all
                             nine states are shown in table 2.3. (The atrazine data are presented later in
                             this chapter.)




                             20
                               While CDC’s sampling strategy was designed to show the geographic distribution of water conditions,
                             it was not designed so that estimates could be made about contaminated wells as a percentage of the
                             total universe of private wells in a particular state or in the nine-state area. The testing was done at
                             wells near the intersections of a 10-mile grid overlaid on a map of each of the nine states.



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                                            and Other Contaminants at Community
                                            Systems and Private Wells




Table 2.3: Results of CDC’s Survey of
the Presence of Contaminants in Water                                                                                              Percentage of
From Private Wells in Nine Midwestern                                                    Percentage of                                 wells with
States                                                                                  wells with total      Percentage of         nitrate levels
                                            State and number of wells                          coliform          wells with         above EPA’s
                                            sampled                                        detectionsa              E. colib             standard
                                            Illinois (540)                                           45.9                 15.4                 15.3
                                            Nebraska (598)                                           37.3                   2.5                14.7
                                            Wisconsin (534)                                          22.8                   2.6                     6.6
                                            Iowa (526)                                               58.6                 20.5                 20.6
                                            Kansas (716)                                             48.7                 16.3                 24.3
                                            Minnesota (718)                                          27.3                   4.5                     5.8
                                            Missouri (632)                                           57.4                 22.6                      9.7
                                            North Dakota (673)                                       35.5                   8.2                13.5
                                            South Dakota (583)                                       40.1                   8.4                10.4
                                            Total (5,520)                                            41.3                 11.2                 13.4
                                            a
                                             CDC’s survey procedure was to test one water sample per private well and note the presence or
                                            absence of any total coliform bacteria.
                                            b
                                             Wells in CDC’s survey were also tested for E. coli. EPA requires community water systems that
                                            detect total coliform bacteria in any water sample to test that sample for fecal coliform bacteria or
                                            E. coli.

                                            Source: CDC.



                                            Other studies have also reported the incidence of contamination with total
                                            coliform bacteria and nitrate. The scope and methodology of these studies
                                            are described below, and their results are summarized in table 2.4. (Note
                                            that these studies were also not limited to the six states we reviewed.)

                                        •   In 1991, the University of Nebraska published a study statistically designed
                                            to estimate the population at risk of ingesting contaminated water from
                                            rural private wells.21 The study gathered test results from 2,195 rural wells
                                            from all of the state’s 93 counties. The selection criteria for the wells
                                            required that they be on property actively engaged in farming and/or at
                                            least 6 acres in size. In 1996, the Nebraska Department of Health and the
                                            University of Nebraska-Lincoln published a follow-up study that reported
                                            on tests done at 1,808 of the original 2,195 private wells. The studies
                                            reported total coliform bacteria in about 18 percent of the wells and
                                            excessive nitrate concentrations in 17 to 19 percent of the wells.
                                        •   In 1990, EPA issued the National Survey of Pesticides in Drinking Water
                                            Wells (Phase I). One of the two objectives of the study was to determine

                                            21
                                             Assessment of Statewide Groundwater Quality Data From Domestic Wells in Rural Nebraska
                                            (Lincoln, Neb.: University of Nebraska Press, 1991).



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                                           the frequency and concentration of pesticides and nitrate in drinking
                                           water wells nationwide. (This study included both community and private
                                           wells.) The survey was designed to yield results that were statistically
                                           representative of the nation’s community and rural private wells. The
                                           study estimated that excessive levels of nitrate were in 2.4 percent of the
                                           rural private wells. (The pesticide results are discussed later.)
                                       •   In 1990, an herbicide-manufacturing company presented to EPA the results
                                           of its National Alachlor Well Water Survey, which included testing for
                                           nitrate. The study sampled 1,430 rural domestic wells in counties that used
                                           alachlor in 1986.22 As such, it is representative of the universe of private,
                                           rural domestic wells in counties where the herbicide was sold. The study
                                           reported excessive nitrate levels in 4.9 percent of the wells. (The data on
                                           alachlor are presented later.)
                                       •   In 1984, EPA issued the National Statistical Assessment of Rural Water
                                           Conditions. The sampling, done in 1978 and 1979, covered 400 counties.
                                           Testing for water quality was done at 2,654 households that used either
                                           private wells, “intermediate systems” (systems with 2 to 14 service
                                           connections), or community water systems. This study reported total
                                           coliform bacteria in 42 percent of the private wells and excessive nitrate in
                                           4.1 percent.

Table 2.4: Summary of Total Coliform
and Nitrate Results From Other                                                    Percentage of samples
Studies Using Statistically                                                       testing positive for total       Percentage of samples
Representative Methodologies               Study’s name and date                  coliform bacteria                exceeding MCL for nitrate
                                           Nebraska Department of                 18 in 1991 study                 17.4 in 1991 study
                                           Health/University of                   15.1 in 1996 studya              18.4 in 1996 studyb
                                           Nebraska, 1991/1996
                                           EPA National Survey of                 Not tested                       2.4
                                           Pesticides in Drinking Water
                                           Wells, 1990
                                           National Alachlor Well Water           Not tested                       4.9
                                           Survey, 1990
                                           EPA National Statistical               42.1 percent                     4.1
                                           Assessment of Rural Water
                                           Conditions, 1984
                                           a
                                            The 1996 results are for 1,805 of the 2,195 wells tested in 1991.
                                           b
                                               The 1996 results are for 1,633 of the 2,195 wells tested in 1991.



                                           In addition to the data described above, data that are not statistically
                                           representative of conditions in a particular state also exist. These data are

                                           22
                                            Alachlor is an herbicide used on corn, soybeans, and peanuts. EPA classifies it as a probable human
                                           carcinogen.



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                              generally consistent with the results just described and are presented in
                              appendix II. The two primary reasons why these data may not be
                              representative are that (1) the tests were done at the request of well
                              owners, who may have had the test done because they suspected
                              problems, or (2) the tests were done at new wells that might have become
                              contaminated with total coliform bacteria during construction and would
                              have had to be disinfected before being put into operation. Some of the
                              results are also from specific studies that did not use statistically valid
                              sampling techniques.


Data Suggest That             EPA, CDC, and others have also gathered data on private wells by type, age,
Contamination Rates Are       and depth. These data suggest that higher contamination rates are
Affected by Characteristics   associated with certain well construction characteristics. The most
                              common well types, which are described in more detail in appendix I, are
of Wells                      known as drilled, driven, bored, and dug. In its 1984 assessment of rural
                              water conditions, EPA concluded that

                              “households served by dug and bored wells, wells in which the water leaves the casing
                              above ground level, wells with inadequate covers, inadequately maintained wells, and
                              shallow wells all tended to have high coliform levels more commonly than those served by
                              wells without those characteristics.”


                              According to data gathered by CDC, bored and dug wells had the highest
                              proportion of contamination. The material used to construct the well
                              casing is related to the well type and appears to affect contamination
                              rates. CDC’s data showed that the brick and concrete tile casings
                              characteristic of dug and bored wells had higher contamination rates than
                              the steel casings characteristic of drilled and driven wells. Other water
                              quality researchers who have analyzed data in Nebraska, Iowa, Kansas,
                              and Ohio have also concluded that the incidence of nitrate contamination
                              is higher in wells with open-jointed casing (i.e., brick or concrete tile) than
                              continuous casing (i.e., plastic or steel).

                              Researchers investigating the incidence of contamination do not all
                              emphasize the significance of the same well construction characteristics,
                              however. For example, a study of private wells in Iowa concluded that “by
                              far the most significant factor explaining water-quality variations is well
                              depth,”23 while a study of nitrate contamination in wells in Kansas




                              23
                                The Iowa State-Wide Rural Well-Water Survey, Iowa Department of Natural Resources (Nov. 1990).



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                            emphasized the age of the well.24 In a statement that applies to both the
                            age and the type of well, water quality scientists from the University of
                            Nebraska concluded that evidence supports

                            “the widely held belief that modern well construction practices provide an effective barrier
                            to surface contamination and can reduce the incidence of nitrate contamination in
                            domestic rural wells.”25


                            Other factors that can influence water quality are discussed in chapter 3.


                            Limited data have been collected in the six states and elsewhere on
Data on Private Wells       contaminants such as pesticides, heavy metals, and volatile organic
for Other                   compounds in drinking water from private wells. State and local
Contaminants Are            governments do not require testing for these contaminants, and states’
                            databases show that well owners rarely request such testing. The bulk of
Very Limited and            the data for these contaminants is collected through specialized studies by
Show Low Rates of           government, industry, or academia. In general, the incidence of these
                            contaminants at concentrations above their MCLs is on the order of 0 to
Excessive                   2 percent. The following studies, not all of which used statistically random
Contamination               sampling techniques, provide examples.

                        •   The University of Nebraska and the Nebraska Department of Health issued
                            a report in 1996 that described pesticide data collected for two studies
                            from 1985 through 1989 and during 1994 and 1995. The first study tested
                            water at 2,195 private wells, and the second tested water at a subset of
                            1,808 of the original wells. The wells were all on property that was actively
                            being farmed and/or at least 6 acres in size, and the studies were
                            representative of drinking water conditions under those circumstances.
                            Atrazine has been the most frequently detected pesticide in Nebraska.
                            Atrazine was detected at concentrations above EPA’s MCL in 1.0 percent of
                            the private wells tested in the first study and 2.6 percent in the second
                            study. (All of these later cases were accounted for by 2 of the state’s 13
                            groundwater regions.)
                        •   In the 1994 effort described above, CDC also gathered data on atrazine
                            contamination in 4,847 wells across eight of the nine midwestern states
                            surveyed. Of the wells sampled, the percentage with atrazine above the
                            MCL ranged from 0.0 percent to 0.6 percent for the eight states, with an
                            aggregate percentage of 0.2.

                            24
                             J. Steichen et al., “Contamination of Farmstead Wells by Pesticides, Volatile Organics, and Inorganic
                            Chemicals in Kansas,” Ground Water Monitoring Review (Summer 1988).
                            25
                             R.F. Spalding and M.E. Exner, “Occurrence of Nitrate in Groundwater—A Review,” Journal of
                            Environmental Quality, Vol. 22 (July-Sept. 1993).



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                          Data on Total Coliform Bacteria, Nitrate,
                          and Other Contaminants at Community
                          Systems and Private Wells




                      •   The 1990 National Alachlor Well Water Survey, sponsored by the herbicide
                          manufacturer and representative of rural private wells in counties that
                          used alachlor, estimated that 0.02 percent of the rural private wells in
                          those states had concentrations above the MCL. The study also estimated
                          that 0.1 percent had atrazine concentrations above the MCL. EPA’s
                          representative 1990 National Survey of Pesticides in Drinking Water Wells
                          estimated that 0.6 percent of all rural private wells were contaminated
                          with a pesticide at a level over its MCL or Lifetime Health Advisory Level.
                          The same study estimated that 0.8 percent of community water systems
                          were contaminated with a pesticide at concentrations above these levels.
                      •   Wisconsin’s Department of Agriculture, Trade, and Consumer Protection
                          tested for atrazine in a sample representative of private wells at dairy
                          farms in 1988. Fewer than 1 percent of the wells had concentrations above
                          the state’s enforcement standard (which is the same as EPA’s MCL). In
                          another Wisconsin Department of Agriculture project, the state distributed
                          atrazine testing kits to 2,187 people statewide. This unrepresentative study
                          showed that samples from 1 percent of the wells tested exceeded the
                          state’s enforcement standard.
                      •   The Heidelberg College Water Quality Laboratory has also tested for
                          pesticides in thousands of midwestern private wells whose owners have
                          volunteered for testing since 1987. Although this is not a representative
                          sample, the results show that samples from 1.1 percent of the wells
                          exceeded the MCL for alachlor and that samples from 0.1 percent exceeded
                          the MCL for atrazine.


                          According to EPA and state drinking water officials, testing at community
Contaminated              water systems that detects contaminated groundwater may indicate that
Groundwater May           water in nearby private wells is also contaminated. If a private well and a
Affect Both               community system both obtain their water from groundwater that is
                          contaminated, both may be affected. This is more likely for contaminants
Community Water           that persist in the environment and migrate through the soil to the
Systems and Private       groundwater. These include nitrate, some pesticides, and volatile organic
                          compounds. EPA also noted that naturally occurring contaminants in
Wells                     groundwater, such as radiological compounds, may affect both community
                          and private drinking water wells. In contrast, the presence of total
                          coliform bacteria is likely to be localized to a particular well because they
                          are not especially long-lived or able to travel far through the groundwater.

                          While it is difficult to generalize about the contamination levels that
                          community water system users and private well users face when both
                          obtain water from a contaminated aquifer, there is reason to believe that



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                       Data on Total Coliform Bacteria, Nitrate,
                       and Other Contaminants at Community
                       Systems and Private Wells




                       the users of private wells may face higher exposure levels. First, many
                       community systems treat their water to remove pollutants. The treatment
                       is intended to remove some percentage of the contamination from the
                       source water. In contrast, most private well users do not treat their water,
                       particularly not using a method capable of removing pesticides or organic
                       compounds. Second, community water wells are typically deeper than
                       private wells. Because contamination from human activity usually
                       originates near the surface and then disperses vertically and horizontally,
                       concentrations of contamination are likely to diminish with the distance
                       from the source and depth. Therefore, a shallow private well is likely to
                       tap into contaminated water before a deeper community well does.26


                       SDWA requires that owners and operators of community water systems
SDWA’s Requirement     notify their customers when treated water exceeds the MCL for a particular
for Expanded Public    contaminant. The 1996 amendments to SDWA require EPA to strengthen the
Notification Could     regulations for this requirement. In addition, EPA must develop, by
                       August 1998, regulations that will require more comprehensive public
Benefit Private Well   notification about contaminated drinking water. The owners and operators
Users                  of community water systems will be required to prepare annual reports
                       that provide their customers with data on all detections of regulated
                       contaminants, regardless of whether the detections exceed the MCLs.

                       While only a very small percentage of community water systems violate
                       the MCL for any contaminant other than total coliform bacteria, a
                       substantially larger percentage of systems do find and, if necessary,
                       remove some amounts of other contaminants. The Congress, in
                       reauthorizing SDWA, indicated that it was important for the customers of
                       community water systems to know about the levels of contaminants in the
                       water they consume. Because private well users who are consuming
                       untreated water from the same source may be exposed to even higher
                       levels of contamination, this information is likely to be of interest to them
                       as well, but there is now no requirement to notify them.


                       Drinking water is vulnerable to contamination, and users that do not have
Conclusions            access to complete information about their water cannot be certain that it
                       is safe. Because private wells are not as extensively regulated as


                       26
                        There are possible exceptions to this. One is that the flow of contaminated groundwater from the
                       pollution source may be away from a private well and toward a community well. The reverse, of
                       course, could also be true. Another possible exception concerns contaminants known as light,
                       nonaqueous-phase liquids, such as benzene and petroleum products, that “float” on groundwater—in
                       contrast to dense, nonaqueous-phase liquids that sink and collect toward the bottom of an aquifer.



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                  community water systems and because private well owners do not
                  generally conduct frequent or comprehensive tests of their water, they do
                  not have complete information about its safety.

                  This does not imply that private well users are all at risk or that they
                  should begin to test their water for all of the contaminants regulated by
                  community water systems. That would be unnecessarily expensive. What
                  it does suggest is that when there is information already available from
                  community systems that could alert private well users to possible local
                  contamination problems, these users could benefit from that information.
                  For example, community water systems could provide a copy of their
                  annual water quality report to state and/or local public health agencies,
                  which could then alert private well users to localized contamination
                  problems and advise them to consider having their well tested for specific
                  pollutants, if appropriate. The agencies could publicize the availability of
                  the annual report through the local media, making sure that the notice
                  alerts private well users to the report’s potential relevance to their water
                  supply. With the information from the annual report, private well users can
                  make informed choices about testing or maintenance. Without the
                  information, they may not be aware of potentially harmful contamination.


                  To help ensure that private well users are better informed of potential
Recommendation    contamination problems and associated health risks, we recommend that
                  the Administrator, Environmental Protection Agency, explore options that
                  would provide such well users with information on how to learn more
                  about the quality of their drinking water and the steps they can take to
                  protect their drinking water source from contamination. For example,
                  state and/or local health agencies could use the local media to alert private
                  well users to consider testing their water whenever the testing of a
                  groundwater-supplied community water system detects contamination
                  that could potentially be present in the same geologic formation supplying
                  nearby private wells.


                  EPA officials commented that this report will prove useful in educating the
Agency Comments   public on the threats to private drinking water wells. EPA also noted that it
                  sees its role in protecting the public health as including private well users
                  and providing them with helpful information about drinking water. The
                  agency, therefore, supported the intent of our recommendation but
                  suggested that it give EPA and the states more flexibility and discretion in
                  deciding how to ensure that private well users are better informed about



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their water quality. EPA also suggested that there is a need for general
public outreach to educate consumers on the need for periodic testing of
private drinking water wells. We have made revisions to reflect EPA’s
comments.

CDC  also agreed with the intent of the recommendation. The agency
commented that the data presented in this report could support additional
recommendations. Specifically, CDC pointed to gaps in knowledge that
could be filled by the routine testing of wells and centralized collection of
the test results. CDC also suggested that reductions in the factors that
influence contamination could be achieved through the use of
construction standards, maintenance, inspections, and controls on land
use and siting. We agree that routine testing and centralized data
collection would help fill the gaps in knowledge about the quality of water
from private wells and that steps could be taken to reduce the factors that
contribute to water contamination. However, we do not include such
recommendations because the authority to require them rests with the
states rather than with EPA.

CDC  also commented that this report does not emphasize the water quality
problems of small community water systems and that it compares the
quality of private well water only to that of large community systems. Our
report discusses data on the compliance of community water systems of
all sizes. It also points out that about 85 percent of the community systems
are small and that 80 percent of the systems with at least one MCL violation
between fiscal years 1993 and 1996 were small or very small. Furthermore,
in chapter 3, we refer to a 1994 GAO report that discusses the technical and
financial difficulties of small systems in meeting the requirements of the
drinking water program.

The state representatives generally agreed with the intent of our
recommendation. However, several of the states expressed concern that
implementing the recommendation might place a large burden on
community water systems. In light of these comments and those from EPA,
we have revised the recommendation to provide flexibility in how water
quality information is made available to private well users. The state
representatives also provided other technical clarifications and
suggestions, which we incorporated as appropriate.




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Several Factors Influence the Quality of
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Systems and Private Wells
                       The quality of drinking water supplied by community water systems and
                       private wells can be influenced by a variety of factors. First, the quality of
                       the source from which drinking water is extracted can have a major
                       influence in the quality of water at the tap, particularly if the water is not
                       treated in any way. Construction standards and other controls are
                       designed to ensure that new water systems and private wells are properly
                       constructed and protected from potential sources of contamination. The
                       extent of such controls and how well they are implemented can also
                       influence water quality. Finally, once a new drinking water
                       source—whether a community system or a private well—is constructed,
                       the extent of ongoing oversight and maintenance activities can help
                       determine whether the water will continue to be safe. Activities such as
                       periodic testing and inspections can prevent minor problems from
                       becoming major ones and thus minimize problems that could adversely
                       affect the quality of drinking water.


                       Depending on the extent of treatment, the quality of the water sources
The Condition of the   used to supply community water systems and private wells can be a key
Source Influences      factor in the quality of drinking water delivered at the tap. Both
Drinking Water         groundwater and surface water are vulnerable to contamination from
                       human activities and naturally occurring substances. When a water source
Quality                is contaminated, some form of treatment may be needed to ensure that the
                       water is safe to drink. However, community water systems are much more
                       likely to treat their water than private well owners.

                       According to EPA’s recent survey of community water systems,27
                       81 percent of the systems reported providing some type of treatment for
                       some or all of the water delivered to consumers. Some of the reported
                       treatment, such as water softening and iron and manganese removal, is
                       intended to improve the aesthetic quality of drinking water while other
                       types of reported treatment, such as disinfection and the removal of
                       organic chemicals, may be necessary for compliance with EPA’s
                       health-based quality standards, or MCLs. More significantly, community
                       water systems are required to take corrective action—by treating water or
                       taking other measures—whenever water quality testing detects
                       contamination in excess of the MCLs. Detecting and treating contamination
                       at private wells is generally done at the discretion of individual well
                       owners.


                       27
                        During 1995 and 1996, EPA surveyed a statistically representative sample of community water
                       systems to collect information on their operational and financial characteristics. See Community
                       Water System Survey (EPA-815-R-97-001a and EPA-815-R-97-001b, Jan. 1997).



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                          Limited data are available on the extent to which private well owners treat
                          their drinking water. The Water Quality Association, an industry group
                          representing manufacturers and vendors of home water treatment devices,
                          does not collect data on sales to private well owners. According to the
                          association’s executive director, however, most of the treatment devices
                          sold to the public are water softeners that improve the aesthetic quality of
                          water by removing hardness, iron, and manganese. In addition, the state
                          officials we interviewed believe that well owners rarely treat their water
                          except to improve its aesthetic quality. However, in the shallower levels of
                          the aquifers tapped by private wells, untreated groundwater may contain
                          contaminants such as nitrate and pesticides that can pose health risks.


                          State construction standards and siting requirements play a key role in
Construction              determining the quality of drinking water at the tap and, for private wells
Standards, Siting         and community systems that rely on groundwater sources, protecting the
Requirements, and         aquifer from contamination. All six of the states we visited have
                          established construction standards and siting requirements for community
Other Controls Help       water systems and private wells. However, we found that while these
Reduce Potential for      states have a fairly rigorous approval and inspection process for
                          community systems, there is less oversight of new private wells and less
Contamination             assurance that these wells comply with state requirements.


New Community Systems     In keeping with their status as regulated public water suppliers,
Are Subject to Approval   community systems must go through a rigorous approval process. As a
and Construction          condition of obtaining primacy under EPA’s safe drinking water program, a
                          state must have a process for ensuring that all new or substantially
Requirements              modified public water system facilities will be capable of complying with
                          applicable drinking water regulations. The six states we visited require
                          that detailed plans and specifications for a new or substantially modified
                          community system be prepared and/or approved by a professional
                          engineer. To ensure that such a system is constructed according to the
                          approved plans, the states conduct inspections during construction or,
                          when construction is complete, require a certification from an engineer
                          hired by the system that it was constructed as approved. For new
                          groundwater wells at community systems, some states, such as Nebraska
                          and New Hampshire, require that test wells be drilled to ensure that the
                          water will meet SDWA’s standards. Once the final well has been
                          constructed, the states generally require additional water quality testing
                          before the new system can be brought on line.




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According to a recent EPA survey of drinking water infrastructure needs,28
community water systems must make significant investments in
improvements to their water sources and their treatment, storage, and
water distribution facilities if they are to continue providing water that is
safe to drink. EPA estimates that these systems’ infrastructure needs will
total $138.4 billion over the next 20 years, including $76.8 billion needed
now to meet SDWA’s requirements and protect public health. Many of the
identified needs are related to meeting current or future drinking water
quality standards or replacing facilities that have met the end of their
useful lives and are deteriorating. Furthermore, according to EPA, many
small water systems were improperly designed and constructed in the first
place. EPA’s report states that “many small systems were built without
review of plans and specifications and were not required to adhere to
minimum design and construction standards.” Officials in five of the six
states we visited generally agreed with EPA’s conclusions, particularly for
older systems that were constructed before state approval and
construction requirements were in place. A Wisconsin official told us that
although some systems in the state may fit EPA’s description, they are
exceptions.

State construction standards for community systems include criteria for
siting new facilities so that they are not located close to potential sources
of contamination. All of the states we visited have established minimum
distances, called setback requirements, between a well and specific
sources of contamination, such as landfills and sewage lagoons.
Community water systems may also take steps to protect a larger area
around their water source. In general, this means identifying potential
sources of contamination within a designated area and adopting various
controls, such as zoning or land-use ordinances, to manage existing
sources of contamination and prevent new sources from locating within
the protected area. Depending on the source of their water, community
systems may protect the area around their groundwater well (wellhead
protection) or their surface water intake.

We did not obtain comprehensive information on the extent to which
community systems in the six states are participating in source water
protection programs. However, we learned that California does not have
an approved wellhead protection program29 and that in several other

28
 EPA Drinking Water Infrastructure Needs Survey: First Report to Congress, EPA Office of Water
(EPA 812-R-97-001, Jan. 1997).
29
 A few local communities in the state have received grants directly from EPA to implement wellhead
protection, but, according to California officials, the state is not involved.



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                            states, the approved programs are voluntary for most water systems. In
                            New Hampshire, for example, all new community water systems are
                            required to have wellhead protection programs, but for existing systems,
                            participation is voluntary. Some states allow their water systems to qualify
                            for reduced monitoring for some contaminants as an incentive to
                            participate in the protection program. According to EPA’s January 1997
                            survey of community water systems, over one-third of all community
                            water systems participate in some type of effort to protect source water,
                            such as adopting land use or zoning controls and educating the public on
                            the impact of land use.


States’ Construction        All six of the states we visited have construction standards for private
Standards for New Private   wells. These standards generally specify appropriate materials and
Wells and Efforts to        construction techniques for various types of wells and establish criteria for
                            siting wells and for ensuring that they are protected from contamination.
Ensure Compliance Vary      In most instances, the states’ construction codes are the minimum
                            statewide standards; state and local regulators may establish more
                            stringent requirements if warranted by site-specific geologic or hydrologic
                            conditions. Officials in all six states generally agree that as long as an
                            aquifer is not contaminated, private wells that are (1) constructed in
                            accordance with current standards and (2) located an adequate distance
                            from potential contamination sources will provide good-quality drinking
                            water. However, we found that the states vary in their efforts to ensure
                            that construction and siting requirements are met.

                            According to the National Ground Water Association, CDC, and state
                            drinking water officials, two of the most important elements of well
                            construction for ensuring good-quality drinking water are (1) requirements
                            for sealing or grouting the well to prevent contamination from entering the
                            groundwater30 and (2) criteria for siting the well, including requirements
                            for minimum setback distances between the well and potential
                            contamination sources. We found that these elements vary widely from
                            state to state. For example, Nebraska requires that the annular space (see
                            ftn. 30) be sealed to a minimum depth of 10 feet while in Wisconsin, the
                            minimum ranges from 0 (no grouting required) to 40 feet, depending on
                            the drilling method and the geological conditions. In New Hampshire, well
                            drillers are responsible for ensuring that each well is sealed adequately for

                            30
                              Many wells are constructed in a manner that creates a space between the larger borehole and the
                            well casing. Unless this area, called the annular space, is properly sealed with cement or other grouting
                            material, contaminants may enter the groundwater through runoff from the ground’s surface. In
                            addition, properly sealing the annular space may prevent contamination from a shallow aquifer
                            infiltrating a deeper one.



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    its particular location; the state does not specify any minimum
    requirement for the depth of the seal. According to an official of the
    California Department of Water Resources, which is responsible for
    promulgating well construction standards, the state is proposing to
    increase its requirements for sealing the annular space in private wells
    from a depth of 20 feet to the 50-foot depth required for community water
    systems. Both Illinois and Nebraska are considering an increase in their
    requirements because state officials believe that the current requirements
    may not be sufficiently protective.

    Similarly, the minimum setback distances between a private well and
    various contamination sources also vary among the states we visited. For
    example, the required setback distance from animal enclosures ranges
    from 20 feet in New Hampshire to 100 feet in California and North
    Carolina. The distance required between a well and a septic tank ranges
    from 25 feet in Wisconsin to 100 feet in California and North Carolina.31
    Officials from both California and Wisconsin told us that the setback
    requirements for a private well are not necessarily based on an assessment
    of what distance would be safe. According to an official from the
    Wisconsin Department of Natural Resources, the minimum distance
    required between a private well and a septic tank or other potential source
    of contamination is simply a matter of “what will fit on an average lot.”

    During our visits to the six states, we also obtained information on various
    controls that are intended to ensure that newly constructed private wells
    provide safe drinking water, meet state standards, and are constructed by
    qualified individuals. We found differences in several areas:

•   Permit requirements for new wells. Of the six states we visited, only
    California and Illinois require water well contractors to obtain permits for
    new wells prior to construction. For the most part, the permits are issued
    by county health departments. In Illinois, the permit application must
    contain a plan and drawing of the proposed construction, including the
    lot’s size; the location of property lines and the distances from the
    proposed well to septic tanks, abandoned wells, and other sources of
    contamination; the type of well to be constructed; and the driller’s license
    number. Permit applications may be denied if the available information
    indicates that groundwater at the proposed site is contaminated. Nebraska
    is implementing a permitting program; most of the state’s 23 natural



    31
      North Carolina will approve a setback of 50 feet between a well and a cesspool or septic tank if a lot
    is not large enough for a 100-foot setback.



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    resource districts32 have established groundwater management districts
    that will be responsible for issuing permits for new wells. In North
    Carolina, the permitting requirement is limited to the 22 (out of 87) local
    health boards that have programs for overseeing private wells. Four of the
    72 counties in Wisconsin are authorized to issue permits, and New
    Hampshire does not require permits for new wells.

•   Registration of new wells. All six states require well drillers to prepare a
    drillers’ log or “well completion report” on each new well. These reports
    contain information on the type and depth of the well, the site, the
    materials used in construction, and other information. The reports could
    be useful in helping the state to develop an inventory of private wells, but
    we found that some states question the accuracy of the reporting. For
    example, North Carolina officials estimate that they are notified of about
    60 percent of all new wells through the well completion reports, and in
    Nebraska, where well owners are responsible for filing the drillers’ reports
    with the state, an estimated 40 to 60 percent of new wells are reported.
    California officials raised questions about the reliability of these reports;
    they said that reports from some drillers are “suspiciously similar.”

•   Water quality testing at new wells. Only two of the six states we visited
    require water quality testing at newly constructed wells, and the testing is
    limited to one or two contaminants. Both Illinois and Wisconsin require
    testing for total coliform bacteria, and Illinois also requires that new wells
    be tested for nitrate. Some counties in California and North Carolina
    require testing at new wells, generally for bacteria.

•   Inspection of new wells. Of the six states we visited, only California and
    Illinois require the inspection of new private wells to ensure that they are
    built in accordance with state standards. In California, under the state’s
    model well ordinance, counties must inspect all new wells to ensure that
    the annular space is properly sealed and that potentially contaminated
    surface water or shallow subsurface water is thus prevented from flowing
    into the well along the outside of the well casing. The counties may also
    make an initial inspection of the proposed drilling site, inspect the
    completed well, and conduct other inspections as appropriate. State
    officials told us that enforcement of the state’s well construction standards
    varies from county to county. Illinois also requires the inspection of all
    new wells—either by the state or an approved local agency—to determine
    whether construction and siting requirements have been met. In North


    32
      Nebraska has established 23 natural resource districts to protect and manage natural resources at the
    local level.



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    Carolina, 22 of the state’s 87 local health boards are authorized to inspect
    new wells, but state officials were not sure about the extent to which
    inspections were actually conducted. New Hampshire officials told us that
    they do not have the resources to inspect new wells, and neither Nebraska
    nor Wisconsin has an inspection program for new wells.33


    Licensing of water well contractors. According to the chief of Nebraska’s
    water well standards program, the first line of defense in avoiding well
    construction problems is the water well contractor. With the exception of
    North Carolina, the states we visited all have programs to license well
    drillers and pump installers. North Carolina officials told us that anyone
    who can pay the $50 fee can register as a well driller regardless of his/her
    experience or technical proficiency. However, a proposal for licensing
    water well contractors is before the state legislature; under this proposal,
    well drillers and pump installers would have to pass a written exam and a
    skills test. The state well drillers’ association supports the licensing
    proposal.34

•   Public education programs. A variety of state and local
    organizations—including public health, environmental protection, and
    agriculture agencies and the well-drilling industry—are involved in efforts
    to educate consumers about drinking water and groundwater protection.
    For example, both EPA and the states have published information
    pamphlets that advise well owners of the importance of locating wells
    away from septic tanks and other sources of contamination and avoiding
    the use or storage of dangerous chemicals near the wellhead. In addition,
    several of the states we visited participate in a program known as
    Farm*A*Syst, which is designed to provide farmers and rural homeowners
    with the tools they need to identify pollution risks on their property,
    including risks to their private wells. The Farm*A*Syst program has been
    jointly sponsored by the U.S. Department of Agriculture and EPA since
    1991. Some state and local agencies, such as county extension services,
    offer free water quality testing to private well owners.




    33
      In Wisconsin, 4 of the state’s 72 counties have programs to inspect new well construction.
    34
     According to data filed in support of North Carolina’s proposal to establish a licensing program for
    well drillers, 15 states, including North Carolina, do not have a licensing and certification program for
    well drillers and pump installers.



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                              While the proper construction and siting of community water systems and
Ongoing Oversight             private wells may be the most important safeguards against contaminated
and Maintenance Help          drinking water, ongoing oversight is also necessary to ensure that water
Ensure That Existing          continues to be safe. Community water systems are subject to periodic
                              testing, maintenance, and inspection requirements. States are responsible
Sources of Drinking           for overseeing community water systems to ensure that they meet the
Water Continue to             requirements and to take corrective action when problems are identified.
                              For private wells, however, the primary responsibility for routine
Provide Good-Quality          monitoring and maintenance rests with individual homeowners. For the
Water                         most part, states play a minimal role in the oversight of existing private
                              wells.


Community Systems Are         Community water systems are subject to extensive requirements for
Subject to Periodic Testing   testing water quality. In addition to periodic testing, community systems
and Inspection                must undergo comprehensive inspections, called sanitary surveys,
                              performed by state or county inspectors. According to EPA’s guidance,
Requirements                  sanitary surveys should entail a detailed review of all aspects of a water
                              system’s design, operation, and maintenance, including an inspection of
                              the water source, treatment and storage facilities, and distribution system.
                              In addition, a sanitary survey can provide regulators with an opportunity
                              to establish a “field presence” with the owners and operators of water
                              systems and to educate them about proper monitoring and sampling
                              procedures, as well as any changes in regulations. States see sanitary
                              surveys as one of the most important tools they can use to help ensure the
                              capability of water systems to deliver safe drinking water. The six states
                              we visited had a policy of inspecting their community water systems at
                              least once every 2 to 5 years.

                              When problems are identified through water quality testing or sanitary
                              surveys, federal and state regulations require community water systems to
                              correct these problems. For example, if periodic testing discloses
                              contamination in excess of allowable levels, water systems must treat the
                              water or take other steps, such as finding a new water source or
                              consolidating with a neighboring system, to comply with water quality
                              standards. If the systems fail to come into compliance, they are subject to
                              enforcement action by the states or EPA. Sanitary surveys also detect some
                              serious problems with a direct impact on water quality, but more often,
                              they identify less significant operational or maintenance deficiencies that,
                              if left unaddressed, could become major problems. Timely corrective
                              action helps ensure that drinking water will continue to be safe.




                              Page 39                                    GAO/RCED-97-123 Drinking Water Quality
Chapter 3
Several Factors Influence the Quality of
Drinking Water From Community Water
Systems and Private Wells




Despite these safeguards, we have previously reported concerns about
several aspects of EPA’s safe drinking water program and how it is being
implemented by states and community water systems. On the basis of a
nationwide questionnaire and a review of 200 sanitary surveys in four
states (Illinois, Montana, New Hampshire, and Tennessee), we reported in
1993 that sanitary surveys were often deficient in how they are conducted,
documented, and/or interpreted and that deficiencies disclosed in the
surveys frequently went uncorrected.35 In 1994, we reported that small
community water systems, which comprise about 85 percent of all
community systems, often lack the technical or financial capability to
meet the requirements of the drinking water program.36 We found that the
lack of reliable cost and performance data on affordable alternative
technologies, inadequate authority to address nonviable water systems,
state resource constraints, and other barriers have impeded efforts to help
bring the systems into compliance. We also reported that as the
requirements for the drinking water program expanded after the 1986
amendments to SDWA, states lacked the resources to fully implement key
oversight and quality assurance activities, such as conducting sanitary
surveys and providing technical assistance to small water systems.37

With the passage of the 1996 amendments to SDWA, the Congress has
slowed the pace of regulation and provided significant new funding for
state oversight programs and loans for capital improvements to
community water systems. In addition, the 1996 amendments require EPA
to identify technologies for small water systems that are affordable and
feasible for achieving compliance with MCLs and establish other programs
and requirements designed to improve the capacity of small water systems
to meet SDWA’s requirements.




35
  Drinking Water: Key Quality Assurance Program Is Flawed and Underfunded (GAO/RCED-93-97, Apr.
9, 1993).
36
 Drinking Water: Stronger Efforts Essential for Small Communities to Comply With Standards
(GAO/RCED-94-40, Mar. 9, 1994).
37
  See Drinking Water: Widening Gap Between Needs and Available Resources (GAO/RCED-92-184, July
6, 1992) and Drinking Water Program: States Face Increased Difficulties in Meeting Basic
Requirements (GAO/RCED-93-144, June 25, 1993).



Page 40                                              GAO/RCED-97-123 Drinking Water Quality
                            Chapter 3
                            Several Factors Influence the Quality of
                            Drinking Water From Community Water
                            Systems and Private Wells




Well Owners Are             Private well owners are responsible for ensuring that their wells continue
Responsible for Ongoing     to provide good-quality drinking water. None of the six states we visited
Oversight and Maintenance   requires periodic water quality testing or conducts routine inspections at
                            existing private wells. Most testing at existing private wells is done at the
of Existing Private Wells   discretion of the well owners or when required by lending institutions at
but Often Are Unaware of    real estate transfers. Although Wisconsin does not have a formal program
Their Importance            for inspecting or monitoring existing wells, the state will test the quality of
                            water from wells located in areas “at risk” for pesticides or volatile organic
                            compounds. Similarly, North Carolina is conducting free nitrate testing in
                            private wells located near intensive livestock operations. (See app. II for
                            the results of tests in 1995-96.)

                            Although none of the states we visited conducts routine inspections of
                            private wells, some state or county agencies will inspect wells at the
                            request of individual well owners. For example, Nebraska offers a
                            technical assistance program to private well owners and will inspect the
                            condition of the well and look for potential sources of contamination.
                            North Carolina also conducts inspections in response to consumers’
                            complaints; the state receives more than 700 complaints each year from
                            home or business owners because of problems with their wells or pumps.
                            State officials told us that inspectors invariably find that the problems are
                            due to improper well construction or pump installation.38 New Hampshire
                            does not have the resources to inspect new or existing wells; state officials
                            told us that they have conducted only four or five inspections over the past
                            12 years, generally in response to consumers’ complaints. According to a
                            New Hampshire official, the state licensing board for water and well pump
                            contractors hears several consumer complaints each year. Improperly
                            constructed wells must be repaired or replaced by the licensed contractor.

                            Despite various efforts to educate consumers about these issues, officials
                            in several states believe that many homeowners are not aware of the need
                            to regularly inspect their wells to check for signs of deterioration, identify
                            needed maintenance, and ensure that the wells are protected from
                            contamination. The importance of routine oversight and maintenance of
                            existing wells is evident from the results of CDC’s survey of private wells in
                            nine midwestern states. The survey identified a strong correlation between
                            high rates of contamination and older, shallower wells. Many of the wells
                            in which bacterial or nitrate contamination was detected showed evidence
                            of deterioration or faulty construction, such as cracked well casings,
                            which would have been revealed by routine inspections.

                            38
                             Prior to about 15 years ago, North Carolina conducted random inspections of new and existing
                            private wells, focusing on well drillers suspected of performing inadequate work. However, the state
                            no longer has the resources to conduct random inspections.



                            Page 41                                                GAO/RCED-97-123 Drinking Water Quality
Chapter 3
Several Factors Influence the Quality of
Drinking Water From Community Water
Systems and Private Wells




Data obtained in CDC’s survey indicate that many of the 5,520 wells would
not meet current construction standards. For example, 2,051 (or
37 percent) of the wells had one or more openings—including holes or
cracks in the well casing, openings between the lid and the casing, and
faulty seals around the electric line inlet in the well cap—through which
contamination could easily enter the well.39 CDC’s survey also found that of
the 1,873 wells with a vent to allow air into the well, 655 (35 percent) did
not have the vent properly screened to keep out animals and insects. While
improper well construction does not guarantee poor-quality drinking
water, it does increase the risk of contamination and the importance of
periodic testing and inspection.

States vary in the extent of their authority to enforce well construction
standards and regulate the well drillers responsible for implementing
them. For example, several states have the authority to suspend or revoke
the license of a water well contractor who violates well construction
standards. In contrast to other states, North Carolina does not license well
drillers, and state officials told us that the state has very little enforcement
authority over well drillers. If the state or a county finds a well that was
not properly constructed, the well driller is given 30 days to correct the
problem or is subject to monetary penalties. Corrective action can include
abandonment of the well.

Even where adequate enforcement authority exists, its use depends on
whether states or local agencies become aware of problems and are
willing to deal with them.40 Neither Nebraska nor New Hampshire inspects
new wells, and inspections are limited to certain counties in North
Carolina and Wisconsin. An official from California’s Department of Water
Resources, citing the potential conflict between enforcing well
construction standards and promoting development, said that
enforcement of the standards varies from county to county.




39
 For another 1,216 wells included in the survey (22 percent), the applicable questions were left blank
or the surveyors were unsure about the existence of improper openings.
40
  We did not collect information on the extent to which the states used their enforcement authority to
force well drillers to correct identified problems or to suspend or revoke well drillers’ licenses.



Page 42                                                 GAO/RCED-97-123 Drinking Water Quality
Page 43   GAO/RCED-97-123 Drinking Water Quality
Appendix I

Description of Common Well Construction
Methods

                 Many types of wells are currently in use, including some that are
                 technologically obsolete. The following is a brief description of the most
                 common well construction methods:

             •   Drilled well. This is the most common type of private well. It is
                 constructed by either a cable tool or a rotary method, usually to depths of
                 50 feet or more, with a diameter of 4 to 6 inches. It may have the capacity
                 to provide water for households, industry, irrigation, and community
                 systems.
             •   Driven well. These wells are generally shallow and typically have a small
                 diameter of 1.5 to 3 inches. They are constructed without the aid of any
                 drilling or boring device. Instead, a series of threaded pipes are driven into
                 the ground with a heavy weight. Driven wells are feasible where the water
                 table is shallow and the ground is a permeable sandy soil.
             •   Bored well. These wells are typically 10 to 100 feet deep, 8 to 36 inches in
                 diameter, and built with hand-operated or power-driven augers.
             •   Dug well. These are shallow, large-diameter wells constructed by
                 excavating with power machinery or hand tools instead of drilling or
                 driving. The sides of the well may be supported by brick, fieldstone, or
                 wood, rather than steel piping. Dug wells are the most “old fashioned” of
                 the well types, as well as the most vulnerable to contamination, because
                 contaminated surface water can easily enter the top of the well or
                 contaminated shallow groundwater can seep through the sides.




                 Page 44                                   GAO/RCED-97-123 Drinking Water Quality
Appendix II

Data on Contamination by Total Coliform
Bacteria and Nitrate at Private Wells


Table II.1: Data on Contamination by Total Coliform Bacteria at Private Wells
                                                                                                           Data collection process
                                       Location,                   Percentage of wells                   Nonrandom
                                       approximate number          with total coliform                     selection          New          Owner’s
Source of data                         of samples, and date        contamination and date                  processa          wellsb        requestc
Illinois Department of Public Health   Illinois,                   32.2 in 1994
                                       9,500 in 1994,              33.3 in 1995
                                       9,200 in 1995                                                                               X             X
North Carolina State Laboratory of     North Carolina, 23,000      24.9 in 1995
Public Health                          in 1995,                    24.0 in 1996
                                       22,000 in 1996d                                                                             X             X
University of Wisconsin Cooperative    Wisconsin,                  14 during 1985-96
Extension                              27,700 during 1985-96                                                                                     X
Iowa State-Wide Rural Well-Water       Iowa, 686 sites during      44.6 during 1988-89
Survey                                 1988-89                                                                       X
                                            a
                                             The wells tested for this survey were not selected using a statistically randomized design.
                                            b
                                             The state data contain an unknown proportion of results from tests at newly constructed wells.
                                            These states require that new wells be disinfected before being put into service. Therefore,
                                            contamination at these wells may have been eliminated before they were put into service.
                                            c
                                             Data generated from tests requested by well owners may not be representative if well owners
                                            test because they suspect a problem.
                                            d
                                                Based on 11 months of sampling.




                                            Page 45                                                 GAO/RCED-97-123 Drinking Water Quality
                                            Appendix II
                                            Data on Contamination by Total Coliform
                                            Bacteria and Nitrate at Private Wells




Table II.2: Data on Contamination by Nitrate at Private Wells
                                       Location, approximate                Percentage of wells with               Data collection process
                                       number of samples, and               nitrate above EPA’s                     Nonrandom                 Owner’s
Source of data                         date                                 standard of 10 ppma              selection processb               requestc
Illinois Department of Public Health   Illinois,                            10.3 in 1994
                                       6,000 in 1994,                       10.0 in 1995
                                       6,200 in 1995                                                                                                X
Wisconsin Cooperative Extension        Wisconsin,                           10.2 during
Service                                27,000 during                        1985-96
                                       1985-96                                                                                                      X
Wisconsin Department of Natural        Wisconsin, 4,300, since 1988 17.9
Resources                                                                                                                                           X
                                                                                            d
North Carolina Department of           North Carolina, 948 wells     9.4 in 1995-96
Environment, Health, and Natural       adjacent to intensive
Resources                              livestock operations, 1995-96                                                               X                X
North Carolina Statewide Nitrate       North Carolina,                      3.2 in 1989-90
Survey                                 9,000 in 1989-90                                                                            X
Water Quality Laboratory, Heidelberg   Ohio, Illinois, Indiana,             3.4 during
College, Ohio                          Kentucky, and West Virginia,         1987-95
                                       35,000 during
                                       1987-94                                                                                                      X
Iowa State-Wide Rural Well-Water       Iowa, 686 sites during               18.3 during
Survey                                 1988-89                              1988-89                                                X
Kansas Farmstead Well Contamination Kansas, 103 during 1985-86              28.2 during
Survey                                                                      1985-86                                                X
                                            a
                                             Parts per million.
                                            b
                                                The wells tested for this survey were not selected using a statistically randomized design.
                                            c
                                             Data generated from tests requested by well owners may not be representative if well owners
                                            test because they suspect a problem.
                                            d
                                             In this study, North Carolina reported the percentage of private wells with nitrate concentrations
                                            above 9.5 parts per million.




                                            Page 46                                                   GAO/RCED-97-123 Drinking Water Quality
Appendix III

Major Contributors to This Report


                       Luther Atkins, Assistant Director
Resources,             Ellen Crocker, Evaluator-in-Charge
Community, and         Ross Campbell, Evaluator
Economic               Karen Keegan, Attorney
                       Gerald Laudermilk, Evaluator
Development Division   Stephen Licari, Evaluator
                       Allan Rogers, Assistant Director




(160362)               Page 47                              GAO/RCED-97-123 Drinking Water Quality
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