SAN FRANCISCO, CA · Sonoma County

SONOMA COUNTY MUTUAL WATER COMPANY 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): CA4900640
System type: Community Water System
Population served: 40
Service connections: 18
Ownership: privately owned
Water source: surface water (rivers, lakes, or reservoirs)

Violation history

Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
July 23, 2020 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
August 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
July 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
June 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
May 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
April 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
March 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
February 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
January 1, 2019 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
November 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
October 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
September 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
August 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
July 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
June 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
May 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
April 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
February 1, 2018 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
December 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
November 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
October 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
September 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
August 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
July 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
June 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
April 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
February 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
January 1, 2017 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
December 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
November 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
October 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
September 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
August 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
June 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
May 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
April 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
March 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
February 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
January 1, 2016 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
December 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
November 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
September 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
August 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
July 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
June 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
May 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
April 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
February 1, 2015 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
December 1, 2014 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
October 1, 2014 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
September 1, 2014 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
August 1, 2014 – November 19, 2020
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
October 1, 2013 – November 19, 2020
Resolved
Notification, Public
—
No contaminant on record
September 1, 1984 – September 30, 1984
Archived
Notification, Public
—
No contaminant on record
August 1, 1984 – August 31, 1984
Archived
Notification, Public
—
No contaminant on record
July 1, 1984 – July 31, 1984
Archived
Notification, Public
—
No contaminant on record
June 1, 1984 – June 30, 1984
Archived
Notification, Public
—
No contaminant on record
April 1, 1984 – April 30, 1984
Archived
Notification, Public
—
No contaminant on record
March 1, 1984 – March 31, 1984
Archived
Notification, Public
—
No contaminant on record
February 1, 1984 – February 29, 1984
Archived
Notification, Public
—
No contaminant on record
January 1, 1984 – January 31, 1984
Archived
Notification, Public
—
No contaminant on record
December 1, 1983 – December 31, 1983
Archived
Notification, Public
—
No contaminant on record
November 1, 1983 – November 30, 1983
Archived
Notification, Public
—
No contaminant on record
October 1, 1983 – October 31, 1983
Archived
Notification, Public
—
No contaminant on record
September 1, 1983 – September 30, 1983
Archived
Notification, Public
—
No contaminant on record
August 1, 1983 – August 31, 1983
Archived
Notification, Public
—
No contaminant on record
July 1, 1983 – July 31, 1983
Archived
Notification, Public
—
No contaminant on record
June 1, 1983 – June 30, 1983
Archived
Notification, Public
—
No contaminant on record
May 1, 1983 – May 31, 1983
Archived
Notification, Public
—
No contaminant on record
April 1, 1983 – April 30, 1983
Archived
Notification, Public
—
No contaminant on record
March 1, 1983 – March 31, 1983
Archived
Notification, Public
—
No contaminant on record
February 1, 1983 – February 28, 1983
Archived
Notification, Public
—
No contaminant on record
January 1, 1983 – January 31, 1983
Archived
Notification, Public
—
No contaminant on record
December 1, 1982 – December 31, 1982
Archived
Notification, Public
—
No contaminant on record
November 1, 1982 – November 30, 1982
Archived
Notification, Public
—
No contaminant on record
October 1, 1982 – October 31, 1982
Archived
Monitoring, Regular
—
Gross Alpha, Excl. Radon and U
October 1, 1981 – September 30, 1982
Archived
Monitoring, Regular
—
Gross Alpha, Excl. Radon and U
October 30, 1980 – October 29, 1981
Archived

Resolved addressed and confirmed by the stateArchived closed in EPA's records (typically due to age or a data correction)

Period	Violation	Contaminant / rule	Health-based	Status
July 23, 2020 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
August 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
July 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
June 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
May 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
April 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
March 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
February 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
January 1, 2019 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
November 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
October 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
September 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
August 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
July 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
June 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
May 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
April 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
February 1, 2018 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
December 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
November 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
October 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
September 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
August 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
July 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
June 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
April 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
February 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
January 1, 2017 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
December 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
November 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
October 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
September 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
August 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
June 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
May 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
April 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
March 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
February 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
January 1, 2016 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
December 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
November 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
September 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
August 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
July 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
June 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
May 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
April 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
February 1, 2015 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
December 1, 2014 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
October 1, 2014 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
September 1, 2014 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
August 1, 2014 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
October 1, 2013 – November 19, 2020	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Resolved
September 1, 1984 – September 30, 1984	Notification, Public	—	—	Archived
August 1, 1984 – August 31, 1984	Notification, Public	—	—	Archived
July 1, 1984 – July 31, 1984	Notification, Public	—	—	Archived
June 1, 1984 – June 30, 1984	Notification, Public	—	—	Archived
April 1, 1984 – April 30, 1984	Notification, Public	—	—	Archived
March 1, 1984 – March 31, 1984	Notification, Public	—	—	Archived
February 1, 1984 – February 29, 1984	Notification, Public	—	—	Archived
January 1, 1984 – January 31, 1984	Notification, Public	—	—	Archived
December 1, 1983 – December 31, 1983	Notification, Public	—	—	Archived
November 1, 1983 – November 30, 1983	Notification, Public	—	—	Archived
October 1, 1983 – October 31, 1983	Notification, Public	—	—	Archived
September 1, 1983 – September 30, 1983	Notification, Public	—	—	Archived
August 1, 1983 – August 31, 1983	Notification, Public	—	—	Archived
July 1, 1983 – July 31, 1983	Notification, Public	—	—	Archived
June 1, 1983 – June 30, 1983	Notification, Public	—	—	Archived
May 1, 1983 – May 31, 1983	Notification, Public	—	—	Archived
April 1, 1983 – April 30, 1983	Notification, Public	—	—	Archived
March 1, 1983 – March 31, 1983	Notification, Public	—	—	Archived
February 1, 1983 – February 28, 1983	Notification, Public	—	—	Archived
January 1, 1983 – January 31, 1983	Notification, Public	—	—	Archived
December 1, 1982 – December 31, 1982	Notification, Public	—	—	Archived
November 1, 1982 – November 30, 1982	Notification, Public	—	—	Archived
October 1, 1982 – October 31, 1982	Notification, Public	—	—	Archived
October 1, 1981 – September 30, 1982	Monitoring, Regular	Gross Alpha, Excl. Radon and U	—	Archived
October 30, 1980 – October 29, 1981	Monitoring, Regular	Gross Alpha, Excl. Radon and U	—	Archived

Resolved addressed and confirmed by the stateArchived closed in EPA's records (typically due to age or a data correction)

Enforcement actions

November 19, 2020State Compliance achieved94 linked violations

Contact

WILLIAMSON, MIKE

415-902-9028

SAN FRANCISCO, CA 94117