HALF MOON BAY, CA · San Mateo County

COASTSIDE COUNTY WATER DISTRICT Water System

Current status

No open violations on record as of July 4, 2026.

This system's next federally required Consumer Confidence Report is due July 1, 2027, under the EPA's revised reporting rule.

Data sourced from the EPA ECHO database (SDWA bulk download), last refreshed July 4, 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)

Violation history

Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
April 1, 2008 – April 30, 2008
Resolved
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
June 1, 2005 – June 30, 2005
Resolved
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
February 1, 2005 – February 28, 2005
Resolved
Maximum Contaminant Level Violation, Monthly (TCR)
Health-based
Coliform (TCR)
January 1, 2004 – January 31, 2004
Resolved
Monitoring, Routine Minor (TCR)
—
Coliform (TCR)
July 1, 2003 – July 31, 2003
Resolved
Maximum Contaminant Level Violation, Monthly (TCR)
Health-based
Coliform (TCR)
January 1, 2002 – January 31, 2002
Resolved
Monitoring, Regular
—
Nitrate
October 1, 2001 – December 31, 2001
Resolved
Monitoring, Regular
—
Nitrate
July 1, 2001 – September 30, 2001
Resolved
Monitoring, Repeat Minor (TCR)
—
Coliform (TCR)
February 1, 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
February 1, 1996 – March 31, 1996	Monitoring, Repeat Minor (TCR)	Coliform (TCR)	—	Resolved

Resolved addressed and confirmed by the state

Enforcement actions

February 27, 2018State Compliance achieved20 linked violations
June 11, 2008State Compliance achieved1 linked violation
June 11, 2008State Administrative/Compliance Order without penalty issued1 linked violation
December 14, 2005State Compliance achieved3 linked violations
July 11, 2005State Public Notification requested2 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
May 16, 2002State Violation/Reminder Notice4 linked violations
February 20, 2002State Violation/Reminder Notice2 linked violations
July 21, 1992State Formal Notice of Violation issued1 linked violation

Contact

ROGREN, MARY

650-276-0889

HALF MOON BAY, CA 94019