HALF MOON BAY, CA · San Mateo County
COASTSIDE COUNTY WATER DISTRICT Water System
Consumer Confidence Report status
COASTSIDE COUNTY WATER DISTRICT must publish a Consumer Confidence Report — the annual drinking water quality report covering calendar year 2026 — by July 1, 2027.
As of August 1, 2026, EPA's federal records show no open violations for COASTSIDE COUNTY WATER DISTRICT.
Data sourced from the EPA ECHO database (SDWA bulk download), last refreshed August 1, 2026. This is a record-keeping and public-information tool — it does not replace California’s official records. Always confirm current status with California before making decisions based on this information.
System facts
- System ID (PWSID)
- CA4110011
- System type
- Community Water System
- Population served
- 18,940
- Service connections
- 6,617
- Ownership
- local government
- Water source
- surface water (rivers, lakes, or reservoirs)
COASTSIDE COUNTY WATER DISTRICT is one of 376 community water systems in California in the 10,001 to 100,000 people size category, serving 18,940 people from surface water.
As of August 1, 2026, its federal record holds 10 entries between 1996 and 2008, all of which EPA lists as closed. Nothing has been added since 2008.
Of the 10, 4 are monitoring and reporting requirements — the category that accounts for about four in five of all violations in EPA's national dataset — rather than findings about the water itself. The record involves the Total Coliform Rules, the Surface Water Treatment Rules, and inorganic chemicals.
Violation history
Treatment Technique (SWTR and GWR)
Health-basedSurface Water Treatment Rule
April 1, 2008 – April 30, 2008
ResolvedTreatment Technique (SWTR and GWR)
Health-basedSurface Water Treatment Rule
June 1, 2005 – June 30, 2005
ResolvedMonitoring of Treatment (SWTR-Filter)
—Surface Water Treatment Rule
February 1, 2005 – February 28, 2005
ResolvedMaximum Contaminant Level Violation, Monthly (TCR)
Health-basedColiform (TCR)
January 1, 2004 – January 31, 2004
ResolvedMonitoring, Routine Minor (TCR)
—Coliform (TCR)
July 1, 2003 – July 31, 2003
ResolvedMaximum Contaminant Level Violation, Monthly (TCR)
Health-basedColiform (TCR)
January 1, 2002 – January 31, 2002
ResolvedMonitoring, Regular
—Nitrate
October 1, 2001 – December 31, 2001
ResolvedMonitoring, Regular
—Nitrate
July 1, 2001 – September 30, 2001
ResolvedMaximum Contaminant Level Violation, Monthly (TCR)
Health-basedColiform (TCR)
November 1, 1998 – November 30, 1998
ResolvedNotification, State
—Coliform (TCR)
February 7, 1996 – March 31, 1996
Resolved
Resolved addressed and confirmed by the state
| Period | Violation | Contaminant / rule | Health-based | Status |
|---|---|---|---|---|
| April 1, 2008 – April 30, 2008 | Treatment Technique (SWTR and GWR) | Surface Water Treatment Rule | Health-based | Resolved |
| June 1, 2005 – June 30, 2005 | Treatment Technique (SWTR and GWR) | Surface Water Treatment Rule | Health-based | Resolved |
| February 1, 2005 – February 28, 2005 | Monitoring of Treatment (SWTR-Filter) | Surface Water Treatment Rule | — | Resolved |
| January 1, 2004 – January 31, 2004 | Maximum Contaminant Level Violation, Monthly (TCR) | Coliform (TCR) | Health-based | Resolved |
| July 1, 2003 – July 31, 2003 | Monitoring, Routine Minor (TCR) | Coliform (TCR) | — | Resolved |
| January 1, 2002 – January 31, 2002 | Maximum Contaminant Level Violation, Monthly (TCR) | Coliform (TCR) | Health-based | Resolved |
| October 1, 2001 – December 31, 2001 | Monitoring, Regular | Nitrate | — | Resolved |
| July 1, 2001 – September 30, 2001 | Monitoring, Regular | Nitrate | — | Resolved |
| November 1, 1998 – November 30, 1998 | Maximum Contaminant Level Violation, Monthly (TCR) | Coliform (TCR) | Health-based | Resolved |
| February 7, 1996 – March 31, 1996 | Notification, State | Coliform (TCR) | — | Resolved |
Resolved addressed and confirmed by the state
Enforcement actions
- June 11, 2008State Administrative/Compliance Order without penalty issued1 linked violation
- June 11, 2008State Compliance achieved1 linked violation
- December 14, 2005State Compliance achieved3 linked violations
- February 18, 2004State Violation/Reminder Notice3 linked violations
- November 24, 2003State Violation/Reminder Notice1 linked violation
- May 16, 2002State Public Notification received6 linked violations
- May 16, 2002State Public Notification requested3 linked violations
- February 20, 2002State Public Notification requested3 linked violations
- August 31, 1992State Compliance achieved13 linked violations
- July 21, 1992State Formal Notice of Violation issued1 linked violation
Common questions
Is COASTSIDE COUNTY WATER DISTRICT required to publish a Consumer Confidence Report?
- Yes. COASTSIDE COUNTY WATER DISTRICT is a community water system, and federal rules (40 CFR 141 Subpart O) require every community water system to publish a Consumer Confidence Report each year.
When is COASTSIDE COUNTY WATER DISTRICT’s next Consumer Confidence Report due?
- COASTSIDE COUNTY WATER DISTRICT’s next Consumer Confidence Report is due by July 1, 2027. The report covers calendar year 2026.
Does COASTSIDE COUNTY WATER DISTRICT have any open drinking water violations on record?
- As of August 1, 2026, EPA's federal records show no open violations for COASTSIDE COUNTY WATER DISTRICT.
What is a Consumer Confidence Report?
- A Consumer Confidence Report (CCR) is the annual drinking water quality report that community water systems must provide to the people they serve. It lists the contaminants detected in the system’s water during the year, where the water comes from, and how the results compare with federal limits. EPA’s revised CCR rule takes effect January 1, 2027, and the first reports in the new format are due July 1, 2027.
Contact
ROGREN, MARY
650-276-0889
HALF MOON BAY, CA 94019