Water quality for ZIP code 94562
ZIP 94562 covers Oakville in Napa County, California, one of 10 ZIP codes in the county. 188 active public water systems serve the county; 56 had an EPA violation in the past three years.
Most likely your provider
Other community water systems in Napa County
27 systems, largest first| System | Serves | Status | Rules violated, 3 yr |
|---|---|---|---|
| American Canyon, City of American Canyon |
18,423 | 1 | |
| Calistoga, City of Calistoga |
5,610 | 2 | |
| St. Helena, City of St. Helena |
5,386 | 2 | |
| Town of Yountville |
2,785 | 0 | |
| Howell Mountain Mutual Water Company |
1,244 | 0 | |
| Veterans Home of California |
1,000 | 1 | |
| Pacific Union College |
758 | 0 | |
| Berryessa Highlands |
715 | 1 | |
| Adventist Health St. Helena Hospital |
617 | 0 | |
| Circle Oaks Water District |
500 | 0 | |
| Berryessa Estates (lbrid) |
474 | 0 | |
| Berryessa Pines Water System |
261 | 2 | |
| Meyers Water Co. |
250 | 1 | |
| Capell Valley Estates |
208 | 2 | |
| Tucker Acres Mutual Water Co. |
200 | 1 | |
| Hess Winery |
100 | 2 | |
| Spanish Flat Water District |
92 | 2 | |
| Linda Vista Mutual Water CO |
90 | 0 | |
| Napa River Ranch |
70 | 5 | |
| Calistoga Farm Worker Center |
67 | 0 | |
| LA Tierra Heights Mutual |
67 | 2 | |
| Mondavi Farm Worker Center |
66 | 0 | |
| River Ranch Farm Worker Center |
66 | 0 | |
| Milton Road Water Company |
39 | 1 | |
| Linda Falls Terrace Mutual |
35 | 0 |
Non-community systems in Napa County (160: schools, campgrounds, workplaces, restaurants)
These systems serve places you visit rather than homes.
About this data
Water systems are matched to Napa County, the county this ZIP code lies in, largest first. Your exact provider depends on your address and connection; the largest community water system in a county is usually the city or town utility.
ZIP code areas and town boundaries come from the U.S. Census Bureau's 2020 ZCTA files.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.