The Safe Drinking Water Act (SDWA) of 1974 was the first federal law mandating drinking-water standards for all public water systems. It was enacted as a result of a federal survey of large and small public drinking-water systems that revealed poor water quality was endangering public health. Major amendments were made to the SDWA in 1986 and 1996.
The SDWA applies to every public water system in the United States. The SDWA authorizes the United States Environmental Protection Agency (US EPA) to set national health-based standards for drinking water to protect against both naturally-occurring and man-made contaminants that may be found in drinking water. Private wells are not regulated under the Safe Drinking Water Act. The EPA encourages, but cannot force, private well owners to have their water tested at least annually for health-threatening contaminants.
Under the 1974 SDWA, public water systems were required to follow water quality standards for particular contaminants. Water systems must be tested for these contaminants and, if necessary, the water must be treated to reduce contaminants to the maximum contaminant levels (MCLs) set for each contaminant.
The SDWA requires EPA to establish National Primary Drinking Water Regulations (NPDWRs) for contaminants that may cause adverse public health effects. The regulations include both mandatory levels (MCLs) and nonenforceable health goals (Maximum Contaminant Level Goals, or MCLGs) for each included contaminant.
The I986 amendment to the SDWA in 1986 set a goal of 83 contaminant standards to be established by 1989 and 25 more contaminants for every three years thereafter. The 1996 amendments created a state revolving loan program to provide loan money to communities needing system upgrades or source-water protection. The 1996 amendments also include, new prevention approaches, improved consumer information and changes to improve the regulatory program. The 1986 Amendment requiring EPA to develop standards for 25 new contaminants every three years was rescinded. EPA has to consider risk and cost–benefits of implementing any particular standard. Community water systems were required to publish annual reports to inform citizens about contaminant levels in their water and their community water system’s performance in meeting drinking-water standards.
All states were required to esablish Source-Water Assessment Program (SWAP). A State assessment program is required to: (1) delineate the boundaries of the areas providing source waters for public water systems, and (2) identify (to the extent practicable) the origins of regulated and certain unregulated contaminants in the delineated area to determine the susceptibility of public water systems to such contaminants. Water systems are required to frequently sample and test the water being delivered. If contaminant levels exceed MCLs, the water system must discontinue use of that source until the level is reduced to below the MCL by treatment, blending, or finding an alternative source. Morevoer, citizens must be advised immediately of actions necessary to prevent disease outbreaks, such as boiling water before drinking in the case of microorganisms, or by switching to bottled water.