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EPA Drinking Water Regulations



Source Water Assessment Program (SWAP)

Under provisions of the Safe Drinking Water Act, states are required to develop comprehensive Source Water Assessment Programs that identify the watersheds that supply public tap water, provide an inventory of contaminants present in the watershed, and assess susceptibility to contamination in the watershed. Source water assessments for the Water Authority’s watersheds were conducted by the Virginia Department of Health. Based on the criteria developed by the state, the Potomac River and the Occoquan Reservoir were determined to be of high susceptibility to contamination. This determination is consistent with the state’s finding of other surface waters (rivers, lakes, streams) throughout the Commonwealth of Virginia.

The assessment consists of maps of the watershed area that was evaluated, an inventory of known land use activities, and documentation of any known source water contamination within the last five years.