County · California
Napa County, California: drinking water records
This overview covers 10 ZIP codes and 31 community water systems in Napa County. It also stands in for 0 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 |
|---|---|---|---|---|---|
| American Canyon, City of CA2810005 | 21,437 | 95 | 0 | 9 | 0 ppb |
| Calistoga, City of CA2810002 | 5,610 | 240 | 4 | 8 | 0 ppb |
| St. Helena, City of CA2810004 | 5,386 | 300 | 0 | 10 | 0 ppb |
| Napa, City of CA2810003 | 84,804 | 164 | 0 | 0 | 0 ppb |
| Town of Yountville CA2810007 | 2,787 | 120 | 0 | 0 | 0 ppb |
| Howell Mountain Mutual Water Company CA2810001 | 1,240 | 0 | 0 | 3 | 0 ppb |
| Veterans Home of California CA2810008 | 1,000 | 0 | 0 | 1 | 0 ppb |
| Berryessa Highlands CA2810013 | 715 | 0 | 0 | 15 | 0 ppb |
| Berryessa Estates (Lbrid) CA2800526 | 474 | 0 | 0 | 4 | 0 ppb |
| Berryessa Pines Water System CA2810009 | 261 | 0 | 0 | 1 | 0 ppb |
| Hess Winery CA2801016 | 250 | 0 | 0 | 1 | 7 ppb |
| Meyers Water Co. CA2800530 | 250 | 0 | 0 | 1 | 8.2 ppb |
| Spanish Flat Water District CA2810014 | 230 | 0 | 0 | 1 | 0 ppb |
| Capell Valley Estates CA2800543 | 208 | 0 | 0 | 1 | 3.3 ppb |
| Sienna Ridge Estates ID1280246 | 81 | 0 | 0 | 1 | 0 ppb |
| Napa River Ranch CA2800531 | 70 | 0 | 0 | 2 | 4.4 ppb |
| La Tierra Heights Mutual CA2800525 | 67 | 0 | 0 | 1 | 0 ppb |
| Milton Road Water Company CA2801080 | 44 | 0 | 0 | 1 | 0 ppb |
| R Ranch at the Lake CA2800593 | 28 | 0 | 0 | 1 | 0 ppb |
| Pacific Union College CA2810012 | 1,958 | 0 | 0 | 0 | 7 ppb |
| Adventist Health - St. Helena Hospital CA2800625 | 817 | 0 | 0 | 0 | 0 ppb |
| Circle Oaks Water District CA2800521 | 500 | 0 | 0 | 0 | 0 ppb |
| Tucker Acres Mutual Water Co. CA2800516 | 200 | 0 | 0 | 0 | 14 ppb |
| Suburban Estates MHP MI0040177 | 150 | 0 | 0 | 0 | 0 ppb |
| Rio Vista MHP NE3121527 | 100 | 0 | 0 | 0 | 0 ppb |
ZIP reports in Napa County
No ZIP report in this county is published yet.
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.