County · California
San Diego County, California: drinking water records
This overview covers 115 ZIP codes and 93 community water systems in San Diego County. It also stands in for 1 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 |
|---|---|---|---|---|---|
| Cal-Am Water Coronado CA3710001 | 106,000 | 95 | 0 | 1 | 0 ppb |
| Camp Pendleton (South) CA3710702 | 42,219 | 120 | 2 | 2 | 0.5 ppb |
| Camp Pendleton (North) CA3710700 | 12,651 | 55 | 1 | 1 | 0.1 ppb |
| San Diego, City of CA3710020 | 1,385,379 | 480 | 0 | 0 | 0 ppb |
| Helix Water District CA3710010 | 277,668 | 120 | 0 | 0 | 0 ppb |
| Otay Water District CA3710034 | 238,008 | 240 | 0 | 0 | 0 ppb |
| Sweetwater Authority CA3710025 | 191,282 | 240 | 8 | 0 | 0 ppb |
| Oceanside, City of CA3710014 | 171,483 | 180 | 0 | 0 | 0 ppb |
| Escondido, City of CA3710006 | 137,044 | 70 | 0 | 0 | 1.1 ppb |
| Vista Irrigation District CA3710027 | 132,430 | 240 | 0 | 0 | 0 ppb |
| Vallecitos WD CA3710002 | 113,500 | 236 | 0 | 0 | 0 ppb |
| Carlsbad MWD CA3710005 | 95,158 | 480 | 0 | 0 | 0 ppb |
| Padre Dam MWD CA3710037 | 93,980 | 240 | 1 | 0 | 1.1 ppb |
| Olivenhain MWD CA3710029 | 86,458 | 120 | 0 | 0 | 0 ppb |
| Poway, City of CA3710015 | 49,888 | 120 | 0 | 0 | 0 ppb |
| San Dieguito WD CA3710021 | 40,405 | 120 | 4 | 0 | 1.1 ppb |
| Ramona Municipal WD CA3710019 | 37,047 | 120 | 0 | 0 | 1.7 ppb |
| Nas North Island & Nab Coronado CA3710750 | 36,990 | 120 | 0 | 0 | 0 ppb |
| Lakeside WD CA3710013 | 35,500 | 176 | 3 | 0 | 0 ppb |
| Fallbrook PUD CA3710008 | 35,237 | 335 | 0 | 0 | 1 ppb |
| Rincon del Diablo MWD (Id-1) CA3710018 | 30,757 | 120 | 1 | 0 | 0 ppb |
| Valley Center MWD CA3710026 | 29,938 | 120 | 0 | 0 | 4 ppb |
| Pechanga 090605013 | 29,100 | 360 | 3 | 0 | 1 ppb |
| Rainbow Municipal WD CA3710016 | 23,536 | 95 | 0 | 0 | 2.7 ppb |
| Santa Fe I.D. CA3710023 | 21,578 | 120 | 2 | 0 | 1.7 ppb |
ZIP reports in San Diego 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: 91980.
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.