Sole Source Aquifers

11/09/25

“How does the U.S. designate an aquifer that’s the only or principal source of drinking water?”

Municipalities in the U.S. use a plethora of different sources for drinking water, from groundwater aquifers to coastal desalination plants. But some communities rely on a single aquifer for their only or principal source of drinking water. If this aquifer gets contaminated, then it could spell huge trouble for the community. To protect themselves, communities can apply to the EPA to have their aquifer designated as a Sole Source Aquifer if they receive 50 percent or more of their water from a single aquifer and have no reasonable alternative sources if the aquifer becomes contaminated. Sole source aquifer designation provides legal benefits for communities such as extra environmental review for projects that may damage the aquifer, increasing public awareness, and open up potential federal grants.