Water quality for ZIP code 91377
ZIP 91377 covers Oak Park in Ventura County, California, one of 29 ZIP codes in the county. 95 active public water systems serve the county; 37 had an EPA violation in the past three years.
Most likely your provider
Your location is within the outer bounds of this system's EPA service area.
Other community water systems in Ventura County
67 systems, nearest firstNon-community systems in Ventura County (27: schools, campgrounds, workplaces, restaurants)
These systems serve places you visit rather than homes.
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Foxfield Riding School |
120 | 0 | 0 | |
|
Ventura Farms |
100 | 0 | 0 | |
|
The Ranch at Live Oak |
82 | 1 | 1 | |
|
Glass House Camarillo Cultivation, LLC |
450 | 0 | 0 | |
|
Laguna Vista School/oceanview School Dis |
377 | 0 | 0 | |
|
Santa Clara School |
39 | 0 | 0 | |
|
Oxnard Pallet Company |
38 | 1 | 0 | |
|
GP Anacapa Foods, Llc. |
50 | 0 | 0 | |
|
Bouquet Multimedia |
100 | 0 | 0 | |
|
Nishi Quality Flowers, Inc. |
92 | 1 | 1 | |
|
Lake Piru Park Uwcd |
960 | 0 | 0 | |
|
State Ready Mix, Inc. Ventura |
25 | 1 | 1 | |
|
Rio Mesa High School/oxnard Uhs |
2,600 | 1 | 1 | |
|
Vulcan Materials Company Cal Mat |
30 | 1 | 1 | |
|
Rio School Dist/rio del Valle School |
820 | 0 | 0 | |
|
Rio School Dist/ Rio Real School |
550 | 0 | 0 | |
|
Beedy Water Company, LLC |
35 | 0 | 0 | |
|
Vineyard Mutual Water Company/industrial |
259 | 0 | 0 | |
|
Thomas Aquinas College |
382 | 1 | 0 | |
|
Pyramid Flowers |
30 | 1 | 0 | |
|
Dennison Park |
102 | 1 | 0 | |
|
Usfs Wheeler Gorge Campground |
500 | 0 | 0 | |
|
Smith Forks Water System |
3,000 | 1 | 0 | |
|
Usfs Chuchupate Ranger Station |
26 | 1 | 1 | |
|
Camp Scheideck |
33 | 1 | 1 | |
|
Channel Islands National Park |
30 | 0 | 0 | |
|
Santa Clara Resources |
30 | 1 | 0 |
About this data
Water systems are matched to Ventura County, the county this ZIP code lies in, nearest to the ZIP code's centre 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. Distances are measured to the centre of the service area EPA publishes for the system.
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.