SONOMA, CA · Sonoma County
DIAMOND A MUTUAL WATER COMPANY Water System
Consumer Confidence Report status
DIAMOND A 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 DIAMOND A 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)
- CA4900562
- System type
- Community Water System
- Population served
- 640
- Service connections
- 194
- Ownership
- privately owned
- Water source
- groundwater (wells)
DIAMOND A MUTUAL WATER COMPANY is one of 728 community water systems in California in the 501 to 3,300 people size category, serving 640 people from groundwater.
As of August 1, 2026, its federal record holds 5 entries between 1981 and 1984, all of which EPA lists as closed. Nothing has been added since 1984.
Of the 5, 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 Miscellaneous Other Rules and the Radionuclides and Revised Rad Rule.
Violation history
Notification, Public
—No contaminant on record
August 1, 1984 – August 31, 1984
ArchivedNotification, Public
—No contaminant on record
July 1, 1984 – July 31, 1984
ArchivedNotification, Public
—No contaminant on record
November 1, 1982 – November 30, 1982
ArchivedNotification, Public
—No contaminant on record
October 1, 1982 – October 31, 1982
ArchivedMonitoring, Regular
—Gross Alpha, Excl. Radon and U
October 1, 1981 – September 30, 1982
Archived
Archived closed in EPA's records (typically due to age or a data correction)
| Period | Violation | Contaminant / rule | Health-based | Status |
|---|---|---|---|---|
| August 1, 1984 – August 31, 1984 | Notification, Public | — | — | Archived |
| July 1, 1984 – July 31, 1984 | 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 |
Archived closed in EPA's records (typically due to age or a data correction)
Enforcement actions
No enforcement actions on record for this system.
Common questions
Is DIAMOND A MUTUAL WATER COMPANY required to publish a Consumer Confidence Report?
- Yes. DIAMOND A 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 DIAMOND A MUTUAL WATER COMPANY’s next Consumer Confidence Report due?
- DIAMOND A MUTUAL WATER COMPANY’s next Consumer Confidence Report is due by July 1, 2027. The report covers calendar year 2026.
Does DIAMOND A 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 DIAMOND A 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
LIEBER, JOE
707-337-6047
SONOMA, CA 95476