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Contact EPA Pacific Southwest Water Division

Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Ground Water

Ground Water Quick Finder
Ground Water Home Class V Wells Cesspools in Hawaii Onsite Sewage Treatment Permits Sole Source Aquifer Source Water Protection Tribal Water Protection Underground Injection Wells

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.

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