Contact EPA Pacific Southwest Groundwater
Pacific Southwest, Region 9
Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations
Ground Water

In the Pacific Southwest, 80% of public water supply systems rely to some extent on ground water. Ground water is vulnerable to contamination from activities occurring on and below the earth's surface. The Safe Drinking Water Act (SDWA) authorizes three EPA ground water protection activities: the Underground Injection Control (UIC) regulatory program, the Sole Source Aquifer (SSA) designation program, and the Source Water Assessment and Protection (SWP) program, which includes Wellhead Protection.
Programs & Resources
- Source Water Protection (SWP) Protecting source water from streams, rivers, lakes or underground aquifers from contamination.
SWP on tribal land - Ground Water Contacts and Partners Who to contact at EPA plus links to state and tribal programs.
- Underground Injection Control (UIC) Regulating underground injection activities to protect ground water
UIC on tribal land - Sole Source Aquifer Program
Pacific Southwest sole source aquifer designations