CLEARLAKE OAKS COUNTY WATER DISTRICT
California — Community Water System — PWSID: CA1710001
System Information
| PWSID | CA1710001 |
| System Name | CLEARLAKE OAKS COUNTY WATER DISTRICT |
| System Type | Community Water System |
| Water Source | Surface 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 | CLEARLAKE OAK |
| ZIP Code | 95423 |
| Address | 12952 East Highway 20 |
| Organization | MANN, DIANNA |
| Phone | 707-998-3322 |
Population & Service
| Population Served | 2,359 |
| Service Connections | 2,161 |
Drinking Water Violations (19)
This water system has 19 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Oct 1, 2023 | Dec 31, 2023 | TTHM | MCL | Yes | No | 83.5 UG/L | 0.080 mg/L | 80 | Resolved | Dec 31, 2023 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Oct 1, 2023 | Dec 31, 2023 | TTHM | MCL | Yes | No | 83.5 UG/L | 0.080 mg/L | 80 | Resolved | Dec 31, 2023 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Apr 1, 2021 | Jun 30, 2021 | TTHM | MCL | Yes | No | .087 MG/L | 0.080 mg/L | .08 | Resolved | Jun 30, 2021 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Apr 1, 2021 | Jun 30, 2021 | TTHM | MCL | Yes | No | .087 MG/L | 0.080 mg/L | .08 | Resolved | Jun 30, 2021 | Stage 2 Disinfectants and Disinfection Byproducts Rule |
| Oct 1, 2019 | — | Lead and Copper Rule | MR | No | No | — | TT | — | Resolved | Jan 22, 2020 | Lead and Copper Rule |
| Oct 1, 2019 | — | Lead and Copper Rule | MR | No | No | — | TT | — | Resolved | Jan 22, 2020 | Lead and Copper Rule |
| Oct 1, 2019 | — | Lead and Copper Rule | MR | No | No | — | TT | — | Resolved | Jan 22, 2020 | Lead and Copper Rule |
| Jan 1, 2019 | Dec 31, 2019 | Nitrate | MR | No | Yes | — | 10 mg/L | — | Resolved | Dec 31, 2019 | Nitrate Rule |
| Jan 1, 2019 | Dec 31, 2019 | Nitrate | MR | No | Yes | — | 10 mg/L | — | Resolved | Dec 31, 2019 | Nitrate Rule |
| Oct 1, 2017 | Oct 31, 2017 | Surface Water Treatment Rule | MR | No | No | — | — | — | Resolved | Oct 31, 2017 | Surface Water Treatment Rule |
| Oct 1, 2017 | Oct 31, 2017 | Surface Water Treatment Rule | MR | No | No | — | — | — | Resolved | Oct 31, 2017 | Surface Water Treatment Rule |
| Jul 1, 2006 | Jul 31, 2006 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Jul 31, 2006 | Surface Water Treatment Rule |
| Jul 1, 2006 | Jul 31, 2006 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Jul 31, 2006 | Surface Water Treatment Rule |
| Jun 1, 2006 | — | Lead and Copper Rule | MR | No | No | — | TT | — | Resolved | Jul 7, 2016 | Lead and Copper Rule |
| Jun 1, 2006 | — | Lead and Copper Rule | MR | No | No | — | TT | — | Resolved | Jul 7, 2016 | Lead and Copper Rule |
| Oct 1, 2005 | Dec 31, 2005 | TTHM | MCL | Yes | No | .082 MG/L | 0.080 mg/L | .08 | Resolved | Dec 31, 2005 | Stage 1 Disinfectants and Disinfection Byproducts Rule |
| Oct 1, 2005 | Dec 31, 2005 | TTHM | MCL | Yes | No | .082 MG/L | 0.080 mg/L | .08 | Resolved | Dec 31, 2005 | Stage 1 Disinfectants and Disinfection Byproducts Rule |
| — | — | — | No | No | — | — | — | — | — | — | |
| — | — | — | No | No | — | — | — | — | — | — |
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.