County · California
Siskiyou County, California: drinking water records
This overview covers 21 ZIP codes and 32 community water systems in Siskiyou County. It also stands in for 6 ZIP codes whose utility has too little EPA data for a page of its own.
System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.
Water systems with the most complete records
| Water system | People served | PFAS survey results | PFAS found | Health-based violations | Lead, 9 in 10 homes at or below |
|---|---|---|---|---|---|
| Yreka, City of CA4710011 | 7,825 | 120 | 0 | 1 | 0.6 ppb |
| Mt. Shasta, City of CA4710008 | 3,642 | 180 | 0 | 5 | 1.4 ppb |
| Lake Shastina C.S.D CA4710013 | 2,790 | 0 | 0 | 1 | 1.7 ppb |
| Dunsmuir, City of CA4710002 | 1,707 | 0 | 0 | 3 | 6.6 ppb |
| Mccloud C.S.D. CA4710006 | 1,317 | 0 | 0 | 3 | 2.4 ppb |
| Montague, City of CA4710007 | 1,264 | 0 | 0 | 2 | 1.6 ppb |
| Happy Camp C.S.D. CA4710012 | 1,100 | 0 | 0 | 1 | 1.6 ppb |
| Dorris, City of CA4710001 | 887 | 0 | 0 | 1 | 0 ppb |
| Tulelake, City of CA4710010 | 856 | 0 | 0 | 1 | 1.6 ppb |
| Siskiyou Lake Highlands Mwc CA4700880 | 549 | 0 | 0 | 1 | 1.0 ppb |
| Grenada Sanitary District CA4700523 | 289 | 0 | 0 | 1 | 7.2 ppb |
| Hornbrook C.S.D. CA4700513 | 280 | 0 | 0 | 5 | 5.9 ppb |
| Lake Siskiyou M.W.C. CA4700549 | 277 | 0 | 0 | 3 | 0.9 ppb |
| Siskiyou Co.Service Area #5/Carrick CA4700521 | 143 | 0 | 0 | 1 | 0.9 ppb |
| Tennant C.S.D. CA4700531 | 75 | 0 | 0 | 2 | 0 ppb |
| Callahan Water District CA4700503 | 70 | 0 | 0 | 1 | 0 ppb |
| Shastina Mobile Estates CA4700884 | 32 | 0 | 0 | 1 | 0 ppb |
| Weed, City of CA4710009 | 2,662 | 0 | 0 | 0 | 0 ppb |
| Etna, City of CA4710004 | 720 | 0 | 0 | 0 | 1.9 ppb |
| Fort Jones, Town of CA4710003 | 695 | 0 | 0 | 0 | 3.1 ppb |
| Siskiyou Co. Rolling Hills Mwc CA4700528 | 300 | 0 | 0 | 0 | 1.9 ppb |
| Fairplay MHP CO0147030 | 215 | 0 | 0 | 0 | 0 ppb |
| Monte Shasta M.W.C. CA4700872 | 150 | 0 | 0 | 0 | 0.9 ppb |
| Cal Ore Mobile Estates CA4700546 | 146 | 0 | 0 | 0 | 0.7 ppb |
| Abrams Lake Mobile Estates CA4700542 | 135 | 0 | 0 | 0 | 0.6 ppb |
ZIP reports in Siskiyou County
No ZIP report in this county is published yet.
These ZIP codes are covered by this overview because their utility has too little EPA data for a separate page: 95568, 96034, 96037, 96050, 96085, 96086.
Sources and scope
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Page generated 2026-09-03.
Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.