Drinking Water—Safety on Tap - Safe Drinking Water Act Of 1974

Federal regulation of drinking water quality began in 1914, when the U.S. Public Health Service established standards for the bacteriological quality of drinking water. The standards applied only to systems that supplied water to interstate carriers such as trains, ships, and buses. The Public Health Service revised these standards in 1925, 1942, and 1962. The 1962 standards, which regulated twenty-eight substances, were adopted by the health departments of all fifty states, even though they were not federally mandated. The Public Health Service continued to be the primary federal agency involved with drinking water until 1974, when the authority was transferred to the EPA. Table 5.3 shows a history of EPA drinking water regulations enacted since 1974.

The SDWA mandated that the EPA establish and enforce minimum national drinking water standards for any contaminant that presents a health risk and is known to, or is likely to, occur in public drinking water supplies. For each contaminant regulated, the EPA was to set a legal limit on the amount of contaminant allowed in drinking water. In addition, the EPA was directed to develop guidance for water treatment, and to establish testing, monitoring, and reporting requirements for water suppliers.

Congress intended that, after the EPA had set regulatory standards, each state would be granted primacy; that is, states would have the primary responsibility for enforcing the requirements of the SDWA. To be given primacy, a state must adopt drinking water standards and conduct monitoring and enforcement programs at least as stringent as those established by the EPA. Forty-nine states and all U.S. commonwealths and territories have received primacy. The EPA implements the drinking water program in Washington, D.C., and on Native American reservations. According to an EPA fact sheet TABLE 5.3
EPA regulations regarding drinking water, complete list by year
SOURCE: "Table 1. Environmental Protection Agency Regulations Regarding Drinking Water, by Year Enacted—United States, 1974–2003," in Morbidity and Mortality Weekly Report, October 22, 2004, http://www.cdc.gov/mmwr/PDF/SS/SS5308.pdf (accessed April 1, 2005)

Regulation	Year
Safe Drinking Water Act (SDWA)	1974
Interim Primary Drinking Water Standards	1975
National Primary Drinking Water Standards	1985
SDWA amendments	1986
Surface Water Treatment Rule (SWTR)	1989
Total Coliform Rule	1989
Lead and Copper Regulations	1990
SDWA Amendments	1996
Information Collection Rule	1996
Interim Enhanced SWTR	1998
Disinfectants and Disinfection By-Products (D-DBPs) Regulation	1998
Contaminant Candidate List	1998
Unregulated Contaminant Monitoring Regulations	1999
Groundwater Rule (proposed)	2000
Lead and Copper Rule—action levels	2000
Long Term 1 Enhanced SWTR	2002
Long Term 2 Enhanced SWTR	2003
Stage 2 D-DBP Rule	2003

updated April 21, 2003, the state of Wyoming had not received primacy over enforcement of the SDWA.

The EPA established the primary drinking water standards by setting MCLs for contaminants that are known to be detrimental to human health. Since 1974 the number of contaminants regulated under the SDWA has quadrupled.

All public water systems in the United States are required to meet the primary standards. Only two contaminants regulated thus far, microorganisms and nitrates, pose an immediate health problem when the standards are exceeded. All other contaminants for which standards have been established must be controlled because ingesting water that exceeds these MCLs over a long period may cause long-term health problems such as cancer, liver or kidney disease, or other harmful effects.

Secondary standards cover aspects of drinking water that have no health risks, such as odor, taste, staining properties, and color. Secondary standards are recommended but not required.

Sole Source Aquifers

Under the SDWA, the EPA has the authority to designate certain groundwater supplies as the sole source of drinking water for a community (referred to as "sole source aquifers"). This designation protects water supplies in areas with few or no alternative sources to the groundwater resource. These aquifers have at least 50% of the population in the area dependent on the aquifer for water supply so that any contamination would result in widespread public harm. If aquifer contamination occurred, an alternative source, if available, would be extremely expensive. The EPA protects these groundwater resources by reviewing any proposed projects within the designated area that are receiving federal money, to ensure that they do not endanger the water source. The first sole source aquifer was designated in 1975, and by 1997 there were seventy-one designated in twenty-five states and territories. According to the EPA, as of February 2005, there were seventy-four sole source aquifers in the United States.

Underground Injection Control Program

The Underground Injection Control Program of the SDWA was created specifically to protect groundwater sources of drinking water. The program regulates wells used by various municipal, commercial, industrial, and agricultural entities to inject fluids underground. These injections are made to dispose of wastes, for hydrocarbon production and storage, or for mineral recovery. The requirements are designed to ensure that the injected fluids stay within the wells and the injection zones, and do not migrate to endanger underground sources of drinking water.

According to the EPA in "State UIC Programs" (http://www.epa.gov/safewater/uic/primacy.html, February 14, 2005), thirty-seven states and territories have primacy (primary enforcement responsibility) for this program. The EPA directly implements ten programs and shares responsibilities with states in six others. A 2002 EPA fact sheet estimated that at that time UIC programs regulated more than 600,000 injection wells and up to 89% of all hazardous waste that is land-disposed in the United States.