Drinking Water:

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

RCED-97-123: Published: Jun 12, 1997. Publicly Released: Jul 18, 1997.

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Pursuant to a congressional request, GAO provided information on the quality of drinking water found at community water systems and private wells, focusing 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.

GAO noted that: (1) much more is known about the quality of drinking water from community water systems than from private wells; (2) 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; (3) 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; (4) a sizable number of systems, although a small percentage of the total, violated standards for radiological contaminants, nitrate, and the herbicide atrazine; (5) violations of other standards were few; (6) for private wells, the available data on water quality are, for the most part, limited to data on total coliform bacteria and nitrate; (7) 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; (8) 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; (9) less extensive data on two commonly used herbicides show much lower levels of contamination in private wells; (10) several factors influence the quality of drinking water obtained from community water systems and private wells; and (11) these factors include the condition of the source from which the drinking water is extracted, 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 ongoing oversight and maintenance activities, such as periodic testing and inspections, that help determine whether the water will continue to be safe.

Recommendation for Executive Action

  1. Status: Closed - Implemented

    Comments: EPA is implementing a number of initiatives that should help educate private well owners to issues about the quality of their drinking water. For example, large public water systems will be required to put information about their drinking water sources and quality on the Internet, and EPA is encouraging smaller systems to do so as well. In addition, EPA believes that modifications to its public notification regulations will heighten public awareness of the potential health risks associated with drinking water contamination and motivate private well owners to check the safety of their supply.

    Recommendation: To help ensure that private well users are better informed of potential contamination problems and associated health risks, the Administrator, EPA, should 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 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.

    Agency Affected: Environmental Protection Agency


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