COASTSIDE COUNTY WATER DISTRICT
California — Community Water System — PWSID: CA4110011
System Information
| PWSID | CA4110011 |
| System Name | COASTSIDE 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 | HALF MOON BAY |
| ZIP Code | 94019 |
| Address | 766 Main Street |
| Organization | ROGREN, MARY |
| Phone | 650-276-0889 |
Population & Service
| Population Served | 18,940 |
| Service Connections | 6,617 |
Drinking Water Violations (31)
This water system has 31 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Apr 1, 2008 | Apr 30, 2008 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Apr 30, 2008 | Surface Water Treatment Rule |
| Apr 1, 2008 | Apr 30, 2008 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Apr 30, 2008 | Surface Water Treatment Rule |
| Jun 1, 2005 | Jun 30, 2005 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Jun 30, 2005 | Surface Water Treatment Rule |
| Jun 1, 2005 | Jun 30, 2005 | Surface Water Treatment Rule | TT | Yes | No | — | — | — | Resolved | Jun 30, 2005 | Surface Water Treatment Rule |
| Feb 1, 2005 | Feb 28, 2005 | Surface Water Treatment Rule | MR | No | No | — | — | — | Resolved | Feb 28, 2005 | Surface Water Treatment Rule |
| Jan 1, 2004 | Jan 31, 2004 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2004 | Total Coliform Rule |
| Jan 1, 2004 | Jan 31, 2004 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2004 | Total Coliform Rule |
| Jul 1, 2003 | Jul 31, 2003 | Coliform (TCR) | MR | No | No | — | 5% of samples | — | Resolved | Jul 31, 2003 | Total Coliform Rule |
| Jul 1, 2003 | Jul 31, 2003 | Coliform (TCR) | MR | No | No | — | 5% of samples | — | Resolved | Jul 31, 2003 | Total Coliform Rule |
| Jan 1, 2002 | Jan 31, 2002 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2002 | Total Coliform Rule |
| Jan 1, 2002 | Jan 31, 2002 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2002 | Total Coliform Rule |
| Jan 1, 2002 | Jan 31, 2002 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2002 | Total Coliform Rule |
| Jan 1, 2002 | Jan 31, 2002 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Jan 31, 2002 | Total Coliform Rule |
| Oct 1, 2001 | Dec 31, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Dec 31, 2001 | Nitrate Rule |
| Oct 1, 2001 | Dec 31, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Dec 31, 2001 | Nitrate Rule |
| Oct 1, 2001 | Dec 31, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Dec 31, 2001 | Nitrate Rule |
| Oct 1, 2001 | Dec 31, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Dec 31, 2001 | Nitrate Rule |
| Jul 1, 2001 | Sep 30, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Sep 30, 2001 | Nitrate Rule |
| Jul 1, 2001 | Sep 30, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Sep 30, 2001 | Nitrate Rule |
| Jul 1, 2001 | Sep 30, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Sep 30, 2001 | Nitrate Rule |
| Jul 1, 2001 | Sep 30, 2001 | Nitrate | MR | No | No | — | 10 mg/L | — | Resolved | Sep 30, 2001 | Nitrate Rule |
| Nov 1, 1998 | Nov 30, 1998 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Nov 30, 1998 | Total Coliform Rule |
| Nov 1, 1998 | Nov 30, 1998 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Nov 30, 1998 | Total Coliform Rule |
| Feb 7, 1996 | Mar 31, 1996 | Coliform (TCR) | Other | No | No | — | 5% of samples | — | Resolved | Mar 31, 1996 | Total Coliform Rule |
| Feb 7, 1996 | Mar 31, 1996 | Coliform (TCR) | Other | No | No | — | 5% of samples | — | Resolved | Mar 31, 1996 | Total Coliform Rule |
| Feb 1, 1996 | Feb 29, 1996 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Feb 29, 1996 | Total Coliform Rule |
| Feb 1, 1996 | Mar 31, 1996 | Coliform (TCR) | MR | No | No | — | 5% of samples | — | Resolved | Mar 31, 1996 | Total Coliform Rule |
| Feb 1, 1996 | Mar 31, 1996 | Coliform (TCR) | MR | No | No | — | 5% of samples | — | Resolved | Mar 31, 1996 | Total Coliform Rule |
| Feb 1, 1996 | Feb 29, 1996 | Coliform (TCR) | MCL | Yes | No | — | 5% of samples | — | Resolved | Feb 29, 1996 | Total Coliform Rule |
| Jun 1, 1992 | Jul 31, 1992 | Coliform (TCR) | MR | No | No | — | 5% of samples | — | Resolved | Jul 31, 1992 | Total Coliform Rule |
| Jun 1, 1992 | Jul 31, 1992 | Coliform (TCR) | MR | No | No | — | 5% of samples | — | Resolved | Jul 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.