SONOMA, CITY OF
California — Community Water System — PWSID: CA4910012
System Information
| PWSID | CA4910012 |
| System Name | SONOMA, CITY OF |
| System Type | Community Water System |
| Water Source | Ground Water |
| Activity Status | Active |
| Owner Type | Local |
| EPA Region | 09 |
| Serves School | No |
| Wholesaler | No |
| First Reported | Mar 22, 1979 |
| Last Reported | Nov 17, 2025 |
Location & Contact
| State | California |
| City | SONOMA |
| ZIP Code | 95476 |
| Address | No, 1 The Plaza |
| Organization | BERGER, MIKE |
| Phone | 707-933-2230 |
Population & Service
| Population Served | 11,725 |
| Service Connections | 4,343 |
Drinking Water Violations (14)
This water system has 14 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Jul 2, 2025 | — | LEAD AND COPPER RULE REVISIONS | RPT | No | No | — | — | — | Unaddressed | — | Lead and Copper Rule Revisions |
| Apr 1, 2021 | Jun 30, 2021 | Arsenic | MR | No | Yes | — | 0.010 mg/L | — | Resolved | Jun 30, 2021 | Arsenic Rule |
| Apr 1, 2021 | Jun 30, 2021 | Arsenic | MR | No | Yes | — | 0.010 mg/L | — | Resolved | Jun 30, 2021 | Arsenic Rule |
| Jan 1, 2020 | Dec 31, 2020 | TTHM | MR | No | Yes | — | 0.080 mg/L | — | Resolved | Dec 31, 2020 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Jan 1, 2020 | Dec 31, 2020 | TTHM | MR | No | Yes | — | 0.080 mg/L | — | Resolved | Dec 31, 2020 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Jan 1, 2020 | Dec 31, 2020 | Total Haloacetic Acids (HAA5) | MR | No | Yes | — | 0.060 mg/L | — | Resolved | Dec 31, 2020 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Jan 1, 2020 | Dec 31, 2020 | Total Haloacetic Acids (HAA5) | MR | No | Yes | — | 0.060 mg/L | — | Resolved | Dec 31, 2020 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Nov 1, 2017 | Nov 30, 2017 | Revised Total Coliform Rule | MON | No | No | — | — | — | Resolved | Nov 30, 2017 | Revised Total Coliform Rule |
| Nov 1, 2017 | Nov 30, 2017 | Revised Total Coliform Rule | MON | No | No | — | — | — | Resolved | Nov 30, 2017 | Revised Total Coliform Rule |
| Jan 1, 2010 | Jan 31, 2010 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2010 | Total Coliform Rule |
| Jan 1, 2010 | Jan 31, 2010 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2010 | Total Coliform Rule |
| Apr 1, 2006 | Jun 30, 2006 | TTHM | MR | No | No | — | 0.080 mg/L | — | Resolved | Jun 30, 2006 | Stage 1 Disinfectants and Disinfection Byproducts Rule |
| Apr 1, 2006 | Jun 30, 2006 | Total Haloacetic Acids (HAA5) | MR | No | No | — | 0.060 mg/L | — | Resolved | Jun 30, 2006 | Stage 1 Disinfectants and Disinfection Byproducts Rule |
| Jan 1, 2006 | Dec 31, 2006 | Nitrate | MR | No | Yes | — | 10 mg/L | — | Resolved | Dec 31, 2006 | Nitrate 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.