Contact EPA Pacific Southwest Water Division
Pacific Southwest, Region 9
Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations
Ground Water
National Links
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Sole Source Aquifer
The EPA's Sole Source Aquifer (SSA) Program was established under Section 1424(e) of the Safe Drinking Water Act (SDWA.) Since 1977, it has been used by communities to help prevent contamination of groundwater from federally-funded projects. It has increased public awareness of the vulnerability of groundwater resources. The SSA program allows for EPA environmental review (PDF) (1pg, 34K) of any project which is financially assisted by federal grants or federal loan guarantees. These projects are evaluated to determine whether they have the potential to contaminate a sole source aquifer.
In Region 9, nine sole source aquifers have been designated:
Maps
Click here for a national layer including all available coverage for Sole Source Aquifers (SSA) that can be used in Geographic Information Systems (GIS)
| State | Sole Source Aquifer Name | Federal Reg. Cit | Publ. Date | Map |
|---|---|---|---|---|
| AZ | Upper Santa Cruz & Avra Basin Aquifer | 49 FR 2948 | 01/24/84 | KMZ PDF (1 pg, 1.3M) |
| AZ | Bisbee-Naco Aquifer | 53 FR 38337 | 09/30/88 | KMZ PDF (1 pg, 175K) |
| CA | Fresno County Aquifer | 44 FR 52751 | 09/10/79 | KMZ PDF (1 pg, 1.3M) |
| CA | Santa Margarita Aquifer, Scotts Valley | 50 FR 2023 | 01/14/85 | KMZ PDF (1 pg, 434K) |
| CA | Campo/Cottonwood Creek | 58 FR 31024 | 05/28/93 | KMZ PDF (1 pg, 321K) |
| CA | Ocotillo-Coyote Wells Aquifer | 61 FR 47752 | 09/10/96 | KMZ PDF (1 pg, 337K) |
| GU | Northern Guam Aquifer System | 43 FR 17867 | 04/26/78 | KMZ PDF (1 pg, 400K) |
| HI | Southern Oahu Basal Aquifer | 52 FR 45496 | 11/30/87 | KMZ PDF (1 pg, 716K) |
| HI | Molokai Aquifer | 59 FR 23063 | 04/20/93 | KMZ PDF (1 pg, 146K) |
A map of all nationally designated SSAs is also available on the Source Water Protection Publications Database.
For more information, please contact the Ground Water Office at
415-972-3971 or visit the national EPA Sole Source Aquifer Program site.
Outreach Documents
Sole Source Aquifer Fact Sheet (PDF) (1pg, 34K)
For Project Planners: What to submit for EPA review of proposed projects (PDF) (1pg, 34K)
Contact Information
See the Sole Source Aquifer section of the Ground Water contacts page.