County · California
Alameda County, California: drinking water records
This overview covers 49 ZIP codes and 18 community water systems in Alameda 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 |
|---|---|---|---|---|---|
| East Bay MUD CA0110005 | 1,442,800 | 626 | 2 | 0 | 0 ppb |
| Alameda County Water District CA0110001 | 344,000 | 420 | 0 | 0 | 0 ppb |
| City of Hayward CA0110006 | 162,954 | 240 | 0 | 0 | 0 ppb |
| Dublin San Ramon Services District CA0110009 | 98,776 | 120 | 0 | 0 | 0 ppb |
| City of Pleasanton CA0110008 | 76,689 | 240 | 8 | 0 | 0 ppb |
| California Water Service - Livermore CA0110003 | 60,414 | 720 | 6 | 0 | 7.5 ppb |
| City of Livermore CA0110011 | 38,892 | 120 | 0 | 0 | 0 ppb |
| Castlewood Domestic Water System CA0105008 | 524 | 0 | 0 | 1 | 41 ppb |
| Mountain View Mobile Home Park NM3550001 | 75 | 0 | 0 | 1 | 13.3 ppb |
| Norris Canyon Property Owners Assn CA0103040 | 50 | 0 | 0 | 1 | 0 ppb |
| Shirk Mobile Home Park NM3520001 | 39 | 0 | 0 | 2 | 0.4 ppb |
| Alameda Point CA0110016 | 1,400 | 0 | 0 | 0 | 0 ppb |
| Trailer Haven Mobile Home Park CA0103041 | 459 | 0 | 0 | 0 | 2.7 ppb |
| Town of Sunol - Sfpuc CA0110012 | 281 | 0 | 0 | 0 | 0 ppb |
| Mile High Mobile Home Park CO0101511 | 209 | 0 | 0 | 0 | 0 ppb |
| Tolas Waterworks Co Op NV0000055 | 190 | 0 | 0 | 0 | 6 ppb |
| Zone 7 Water Agency CA0110010 | 40 | 0 | 0 | 0 | 6.7 ppb |
| Sfpuc-Pleasanton Wells CA0110018 | 1 | 0 | 0 | 0 | not reported |
ZIP reports in Alameda 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.