Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

JavaScript appears to be disabled on this computer. Please click here to see any active alerts.

Map of Sole Source Aquifer Locations

Access the Interactive Map of Sole Source Aquifers

National Geographic Information Systems (GIS) layer of SSAs

Information on sole source aquifers (SSAs) is widely used in assessments under the National Environmental Policy Act and at the state and local level. A national layer, including all available SSA coverages, is available for use in GIS.

In addition to single SSA designated area polygons, some EPA regional offices have delineated GIS layers for:

Streamflow zones
Aquifer recharge areas
Other features at the land surface important for SSA designations

The SSA geospatial data set is available through for use by government agencies, private organizations, and the public. Visit data.gov to download the data.

Map of Sole Source Aquifer Locations

Sole Source Aquifers for Drinking Water