Is HOWELL MOUNTAIN MUTUAL WATER COMPANY required to publish a Consumer Confidence Report?

Yes. HOWELL MOUNTAIN MUTUAL WATER COMPANY 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 HOWELL MOUNTAIN MUTUAL WATER COMPANY’s next Consumer Confidence Report due?

HOWELL MOUNTAIN MUTUAL WATER COMPANY’s next Consumer Confidence Report is due by July 1, 2027. The report covers calendar year 2026.

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.

ANGWIN, CA · Napa County

HOWELL MOUNTAIN MUTUAL WATER COMPANY Water System

Consumer Confidence Report status

HOWELL MOUNTAIN MUTUAL WATER COMPANY 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 HOWELL MOUNTAIN MUTUAL WATER COMPANY.

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): CA2810001
System type: Community Water System
Population served: 1,240
Service connections: 379
Ownership: privately owned
Water source: surface water (rivers, lakes, or reservoirs)

HOWELL MOUNTAIN MUTUAL WATER COMPANY is one of 728 community water systems in California in the 501 to 3,300 people size category, serving 1,240 people from surface water.

As of August 1, 2026, its federal record holds 16 entries between 2004 and 2011, all of which EPA lists as closed. Nothing has been added since 2011.

Of the 16, 1 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 Stage 1 Disinfectants and Disinfection Byproducts Rule.

Violation history

Maximum Contaminant Level Violation, Average
Health-based
TTHM
January 1, 2011 – March 31, 2011
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
January 1, 2011 – March 31, 2011
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
October 1, 2010 – December 31, 2010
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
July 1, 2010 – September 30, 2010
Resolved
Maximum Contaminant Level Violation, Average
Health-based
TTHM
July 1, 2010 – September 30, 2010
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
April 1, 2010 – June 30, 2010
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
October 1, 2009 – December 31, 2009
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
July 1, 2009 – September 30, 2009
Resolved
Maximum Contaminant Level Violation, Average
Health-based
TTHM
July 1, 2009 – September 30, 2009
Resolved
Maximum Contaminant Level Violation, Average
Health-based
TTHM
April 1, 2009 – June 30, 2009
Resolved
Maximum Contaminant Level Violation, Average
Health-based
TTHM
October 1, 2008 – December 31, 2008
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
October 1, 2008 – December 31, 2008
Resolved
Monitoring and Reporting (DBP)
—
Total Haloacetic Acids (HAA5)
July 1, 2008 – September 30, 2008
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Total Haloacetic Acids (HAA5)
July 1, 2008 – September 30, 2008
Resolved
Maximum Contaminant Level Violation, Average
Health-based
TTHM
October 1, 2005 – December 31, 2005
Resolved
Maximum Contaminant Level Violation, Average
Health-based
TTHM
April 1, 2004 – June 30, 2004
Resolved

Resolved addressed and confirmed by the state

Period	Violation	Contaminant / rule	Health-based	Status
January 1, 2011 – March 31, 2011	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved
January 1, 2011 – March 31, 2011	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
October 1, 2010 – December 31, 2010	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
July 1, 2010 – September 30, 2010	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
July 1, 2010 – September 30, 2010	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved
April 1, 2010 – June 30, 2010	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
October 1, 2009 – December 31, 2009	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
July 1, 2009 – September 30, 2009	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
July 1, 2009 – September 30, 2009	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved
April 1, 2009 – June 30, 2009	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved
October 1, 2008 – December 31, 2008	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved
October 1, 2008 – December 31, 2008	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
July 1, 2008 – September 30, 2008	Monitoring and Reporting (DBP)	Total Haloacetic Acids (HAA5)	—	Resolved
July 1, 2008 – September 30, 2008	Maximum Contaminant Level Violation, Average	Total Haloacetic Acids (HAA5)	Health-based	Resolved
October 1, 2005 – December 31, 2005	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved
April 1, 2004 – June 30, 2004	Maximum Contaminant Level Violation, Average	TTHM	Health-based	Resolved

Resolved addressed and confirmed by the state

Enforcement actions

December 31, 2023State Compliance achieved2 linked violations
September 30, 2021State Compliance achieved1 linked violation
February 4, 2021State Administrative/Compliance Order without penalty issued5 linked violations
March 11, 2018State Compliance achieved5 linked violations
August 25, 1993State Administrative/Compliance Order without penalty issued4 linked violations

Common questions

Is HOWELL MOUNTAIN MUTUAL WATER COMPANY required to publish a Consumer Confidence Report?: Yes. HOWELL MOUNTAIN MUTUAL WATER COMPANY 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 HOWELL MOUNTAIN MUTUAL WATER COMPANY’s next Consumer Confidence Report due?: HOWELL MOUNTAIN MUTUAL WATER COMPANY’s next Consumer Confidence Report is due by July 1, 2027. The report covers calendar year 2026.
Does HOWELL MOUNTAIN MUTUAL WATER COMPANY have any open drinking water violations on record?: As of August 1, 2026, EPA's federal records show no open violations for HOWELL MOUNTAIN MUTUAL WATER COMPANY.
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

HIERS, TANNER

707-965-2205

ANGWIN, CA 94508