CALIFORNIA WATER SERVICE - SAN MATEO
California — Community Water System — PWSID: CA4110008
System Information
| PWSID | CA4110008 |
| System Name | CALIFORNIA WATER SERVICE - SAN MATEO |
| System Type | Community Water System |
| Water Source | Surface Water Purchased |
| Activity Status | Active |
| Owner Type | Private |
| EPA Region | 09 |
| Serves School | No |
| Wholesaler | No |
| First Reported | Mar 22, 1979 |
| Last Reported | Nov 17, 2025 |
Location & Contact
| State | California |
| City | SAN JOSE |
| ZIP Code | 95112 |
| Address | 1720 NORTH FIRST STREET |
| Organization | JAMES, SOPHIE |
| Phone | 408-367-8593 |
Population & Service
| Population Served | 102,348 |
| Service Connections | 25,440 |
Drinking Water Violations (3)
This water system has 3 violations recorded in the EPA SDWIS database.
| Begin Date | End Date | Contaminant | Category | Health-Based | Major | Measured | Federal MCL | State MCL | Status | Return to Compliance | Rule |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Jun 1, 1993 | Jun 30, 1993 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Mar 5, 1992 | Surface Water Treatment Rule |
| Jun 1, 1993 | Jun 30, 1993 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Mar 5, 1992 | Surface Water Treatment Rule |
| Oct 1, 1992 | Oct 31, 1992 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Oct 31, 1992 | Total Coliform Rule |
About This Water System
Public water system data comes from the EPA Safe Drinking Water Information System (SDWIS). Systems with violations must notify customers. Contact your water utility for the latest annual water quality report.