The safe drinking water act (sdwa) of 1974 is the primary U.S. federal law regulating the nation's drinking water supply. SDWA applies to all public water systems. The SDWA is implemented through the U.S. Environmental Protection Agency (EPA) but enforcement is mostly delegated to individual states. SDWA sets thresholds or Maximum Contaminant Levels (MCLs) for known and suspected drinking water contaminants. Additionally, SDWA put into place measures to assure that clean groundwater supplies remained uncontaminated. The original SDWA set MCLs for 21 contaminants but through subsequent revisions, the list has grown to over 80. Regulated contaminants include organic contaminants, pesticides, biological contaminants, inorganic compounds, and radionuclides.

SDWA rode the tide of major federal environmental legislation passed during the first half of the 1970s that began with ...