U.S. Congress Requires Safe Drinking Water Summary

  • Last updated on November 10, 2022

The U.S. Environmental Protection Agency was given authority to establish minimum safety requirements for pollutants such as arsenic, barium, cadmium, chromium, fluoride, lead, mercury, nitrates, pesticides, radioactivity, and silver.

Summary of Event

On December 16, 1974, President Gerald R. Ford signed the Safe Drinking Water Act (SDWA), which empowered the Environmental Protection Agency Environmental Protection Agency;Safe Drinking Water Act (EPA) to control the quality of drinking water by establishment of standard regulations and other techniques. Pollution;legislation Water;pollution Safe Drinking Water Act (1974) [kw]U.S. Congress Requires Safe Drinking Water (Dec. 16, 1974) [kw]Congress Requires Safe Drinking Water, U.S. (Dec. 16, 1974) [kw]Safe Drinking Water, U.S. Congress Requires (Dec. 16, 1974) [kw]Drinking Water, U.S. Congress Requires Safe (Dec. 16, 1974) [kw]Water, U.S. Congress Requires Safe Drinking (Dec. 16, 1974) Pollution;legislation Water;pollution Safe Drinking Water Act (1974) [g]North America;Dec. 16, 1974: U.S. Congress Requires Safe Drinking Water[01770] [g]United States;Dec. 16, 1974: U.S. Congress Requires Safe Drinking Water[01770] [c]Laws, acts, and legal history;Dec. 16, 1974: U.S. Congress Requires Safe Drinking Water[01770] [c]Environmental issues;Dec. 16, 1974: U.S. Congress Requires Safe Drinking Water[01770] Gonzalez, Henry Barbosa Johnson, Charles C. Harris, Robert Hilbert, Robert B.

Prior to the law’s passage, a trend toward increasing discharges of agricultural, industrial, and domestic wastewater from a growing population and economy, which in some cases exceeds natural replenishment, caused a “mining” of water, which can have a deteriorating effect on water purity. In addition, the increasing complexity of chemicals used in industry that potentially can make their way into the water supply posed new challenges for pollution abatement.

On November 7, 1974, the Environmental Defense Fund Environmental Defense Fund (EDF) released a report on a study by Dr. Robert Harris that claimed that cancer deaths were associated with chemicals in New Orleans drinking water. Suspicion was directed toward chlorinated organics, which were added to the water either from chlorination of the water supply system or from the chlorination of upstream sewage. Chlorination had been employed for about seventy years as a protective antibacterial measure. Robert B. Hilbert, president of the American Water Works Association American Water Works Association (AWWA), denied there was a crisis regarding water supplies and believed the federal role should involve training and research, not enforcement and surveillance. Despite such objections, the SDWA was eventually passed, 296 votes to 84 votes.

The primary intent of the SDWA was to establish uniform drinking-water quality in all parts of the United States. Its regulations mainly apply to water after it has been treated, as opposed to surface water or groundwater. The SDWA required the EPA to develop two types of standards for water consumed by humans: recommended maximum contaminant levels (RMCLs) and maximum contaminant levels (MCLs). An RMCL quantifies a maximum contaminant concentration based only on scientific and health-related concerns. This is an informational standard and a long-term goal. In contrast, an MCL is a legal limit which, if exceeded, will require action to lower the pollutant concentration to the compliance value.

The SDWA gives the EPA the power to regulate injection of wastes underground and to protect vulnerable and essential aquifers that are a community’s sole source of drinking water. Also, the SDWA requires research on economic, technical, and health-related aspects of drinking water, a rural water supply survey, and funding to enhance the quality of state drinking-water programs. The SDWA created a three-stage process to develop comprehensive drinking-water quality standards. National Interim Primary Drinking Water regulations were promulgated based on generally available technology at the time, the National Academy of Sciences (NAS) was empowered to conduct a survey of health effects stemming from exposure to drinking water pollutants, and Revised Primary Drinking Water Regulations based on NAS findings were to be established. The SDWA provides uniform, stringent standards for pollutants in water which apply to several hundred thousand water supplies. After the law’s passage, starting with interim standards in 1975, the EPA established MCLs for twenty-two pollutants by 1987, and more were added later.

The development of standards was guided by the NAS report completed in 1977 and updated in 1979. Close to one thousand chemicals were identified in the nation’s water supplies. Some believe this number represents only a fraction of those present. Implementation of the SDWA did not proceed without controversy. The EDF sued the EPA for foot-dragging, the AWWA sued the agency for being overzealous, and attempts were made in Congress to weaken the law. In the early 1980’s, the AWWA suit was settled.

The inorganic chemicals that are regulated are arsenic, barium, cadmium, chromium, lead, mercury, nitrate, selenium, silver, and fluoride. For all the inorganics except fluoride, the MCLs are straightforward limits ranging from 2 (for mercury) to 10,000 (for nitrate) parts per billion depending on the pollutant in question. Fluoride Fluoride is a water additive for dental caries prevention. Fluoride MCLs depend on water temperature. Because people drink more water in hotter climates, the fluoride limits attempt to maintain a uniform dose of fluoride throughout the nation. The organic chemicals that are regulated are endrin, lindane, methoxychlor, toxaphene, 2,4-dichlorophenoxyacetic acid (2,4-D), silvex, and total trihalomethanes (TTHM), none of which are naturally occurring substances. The first four are insecticides; the next two are herbicides, typically employed to limit aquatic growth; and trihalomethanes are water disinfection by-products consequent to chlorine, iodine, or bromine additions.

Organic chemicals can enter the water supply from industrial discharge during manufacture or from rainwater runoff. Inorganic chemicals can enter the water supply from industrial activity or from natural action such as soil leaching. Additional standards were promulgated for turbidity, microbiological contaminants, and radioactivity. Not all water comes under SDWA purview. Public drinking-water supplies serving twenty-five or fewer individuals are exempt, as is tap water used for purposes other than drinking, such as irrigation and industrial process water.

The RMCLs, also sometimes called secondary maximum contaminant levels (SMCLs), have been established for substances that are nuisances to the consumer. These substances degrade the aesthetic qualities of water, such as color and odor, and may interfere with water uses such as washing of clothes. At high concentrations, such substances can have health implications. RMCLs have been established for chloride, color, copper, corrosivity, foaming agents, iron, manganese, odor, pH (a measure of water acidity), sulfate, total dissolved solids, and zinc. Monitoring for sodium is mandatory. Corrosive action, mainly a function of pH, must be checked, since corrosive action can leach hazardous materials from the distribution system. Water utilities must examine their distribution systems for components such as lead-soldered pipes and asbestos cement pipes. Also, the EPA has published no adverse response levels for a variety of organics. These are not legal standards, but some municipalities and states have adopted them for well closures.

The SDWA’s provisions are implemented by the EPA, the states, and local water facilities in partnership. The EPA provides overall national guidance. Section 1446 of the SDWA provided for an advisory council, including representatives from private organizations, state and local government, and the general public, to advise the EPA administrator on matters related to the act.

The states have primary SDWA enforcement responsibility within their borders, and the regulations were crafted to be nonduplicative and administratively compatible with existing state activities. This was deemed necessary because of many differences among states in the use and availability of water, geological conditions, underground injection practices, among other things. In the years following the passage of the act, more states and territories had been granted primacy, or full control, over their water programs. The EPA can intervene, however, if a state’s regulations are not as stringent as federal law or if the regulations are not being enforced. This was a major departure from previous practice. Prior to the act, the U.S. government regulated water only on interstate carriers such as trains, although the U.S. Public Health Service Public Health Service, U.S. provided water-quality guidelines. State programs went into effect in June, 1977. The activity levels in states vary widely.


The SDWA helped to diminish drinking-water pollution in many localities, although problems remain. For example, a National Research Council study reported in 1980 that thirty to forty states, including almost all states east of the Mississippi River, had serious drinking-water problems. Problems occur mostly in water systems serving fewer than 10,000 people, as communities with larger systems can usually afford better water-treatment technology and more thoroughly trained personnel. In 1981, for example, more than five years after the law’s passage, 4,430 people became ill from polluted drinking water in thirty-two different disease outbreaks in the United States. Most outbreaks were caused by bacterial contamination.

A 1982 survey of rural U.S. regions revealed that one-third of households, most of which used well water, had bacterial contamination in their water. High lead, mercury, selenium, and cadmium concentrations also were noted. The SDWA, which originally exempted well water, was amended in 1986. A unique groundwater protection measure was introduced, the Wellhead Protection Program, Wellhead Protection Program the first congressionally mandated environmental protection tool to deal comprehensively with groundwater resources. Later provisions called for an EPA evaluation of other drinking-water pollutants, including many synthetic organic chemicals. Pollution;legislation Water;pollution Safe Drinking Water Act (1974)

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Cheremisinoff, Paul N. Water Management and Supply. Englewood Cliffs, N.J.: Prentice Hall, 1993. A good overview of water-quality issues. A particular area of strength is the description of the aesthetic qualities of water.
  • citation-type="booksimple"

    xlink:type="simple">Cotruvo, Joseph A. “Implementation of the Safe Drinking Water Act.” In Drinking Water Quality Enhancement Through Source Protection, edited by Robert B. Pojasek. Ann Arbor: Ann Arbor Science, 1977. This chapter concentrates mainly on the SDWA law itself and its implementation by the EPA.
  • citation-type="booksimple"

    xlink:type="simple">Faust, Samuel D., and Osman M. Aly. Chemistry of Water Treatment. 2d ed. Chelsea, Mich.: Ann Arbor Press, 1998. This is a comprehensive book detailing water remediation measures. The description of water purification procedures is particularly well done.
  • citation-type="booksimple"

    xlink:type="simple">ReVelle, Penelope, and Charles ReVelle. The Environment: Issues and Choices for Society. 3d ed. Boston: Jones & Bartlett, 1988. Presents an assessment of pollution problems from an environmentalist perspective, including an extensive treatment of water resource problems.
  • citation-type="booksimple"

    xlink:type="simple">Sheaffer, John R., and Leonard A. Stevens. Future Water: An Exciting Solution to America’s Most Serious Resource Crisis. New York: William Morrow, 1983. Deals with a wide variety of water purity issues, including those relevant to the SDWA, written from an environmental advocacy standpoint.
  • citation-type="booksimple"

    xlink:type="simple">Smith, V. Kerry, and William H. Desvousges. Measuring Water Quality Benefits. Boston: Kluwer-Nijhoff, 1986. Deals with cost-benefit analyses associated with water-quality issues.
  • citation-type="booksimple"

    xlink:type="simple">Speidel, David R., Lon C. Ruedisili, and Allen F. Agnew, eds. Perspectives on Water Uses and Abuses. New York: Oxford University Press, 1988. A comprehensive work dealing with virtually all aspects of the problem of water use. Particular strong points include its scientific articles, its international perspective, and Charles C. Johnson’s historical review of drinking water.
  • citation-type="booksimple"

    xlink:type="simple">Viessman, W., and Mark J. Hammer. Water Supply and Pollution Control. 7th ed. Englewood Cliffs, N.J.: Prentice Hall, 2004. This volume provides a complete overview of the engineering aspects of water treatment.
  • citation-type="booksimple"

    xlink:type="simple">Williams, Robert B., and G. L. Culp. “Criteria and Standards for Improved Potable Water Qualities.” In Handbook of Public Water Systems. New York: Van Nostrand Reinhold, 1986. This chapter provides a comprehensive view of the issues related to the SDWA. It is particularly strong in presenting historical background, describing the standards themselves, and providing a compilation of the toxic effects associated with the pollutants.

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