Water quality for ZIP code 94548
ZIP 94548 covers Knightsen in Contra Costa County, California, one of 43 ZIP codes in the county. 84 active public water systems serve the county; 21 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 Contra Costa County
38 systems, nearest first| System | Serves | Status | Rules violated, 3 yr | Distance |
|---|---|---|---|---|
| Knightsen Community Water System |
73 | 0 | 0.8 mi | |
| Oakley Mutual Water Company |
170 | 2 | 1.8 mi | |
| Delta Mutual Water Company |
333 | 1 | 2.2 mi | |
| Sandy Point Mobile Home Park |
67 | 2 | 2.5 mi | |
| Dutch Slough Water Works |
49 | 1 | 2.6 mi | |
| Willow Park Marina |
380 | 1 | 2.6 mi | |
| Marina Mobile Manor |
75 | 0 | 2.6 mi | |
| Sandmound Mutual |
100 | 2 | 2.8 mi | |
| Farrar Park Property Owners |
140 | 0 | 2.8 mi | |
| Bethel Island Mutual Water CO |
123 | 1 | 2.9 mi | |
| Big Oak Mobile Home Park Water |
156 | 0 | 2.9 mi | |
| Anglers Subdivision 4 |
99 | 1 | 3.0 mi | |
| Orwood Resort |
350 | 2 | 3.3 mi | |
| Angler S Ranch #3 |
60 | 1 | 3.3 mi | |
| Bethel Island Estates |
200 | 0 | 3.7 mi | |
| Pleasantimes Mutual Water CO |
644 | 0 | 3.8 mi | |
| Bethel Island MHC |
185 | 0 | 4.0 mi | |
| Russos Mobile Park |
110 | 2 | 4.4 mi | |
| Riverview Water Association |
230 | 1 | 4.5 mi | |
| Ccwd/brentwood Wtp |
0 | 0 | 4.5 mi | |
| Brentwood Brentwood |
64,513 | 0 | 4.5 mi | |
| Willow Mobile Home Park |
481 | 0 | 4.6 mi | |
| Randall-Bold Water Treatment Plant |
1 | 0 | 4.6 mi | |
| Town of Discovery Bay |
16,790 | 0 | 5.2 mi | |
| Colonia Santa Maria |
32 | 2 | 5.4 mi |
Non-community systems in Contra Costa County (45: schools, campgrounds, workplaces, restaurants)
These systems serve places you visit rather than homes.
About this data
Water systems are matched to Contra Costa 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.