OAKLEY, CA · Contra Costa County
DIABLO WATER DISTRICT Water System
Consumer Confidence Report status
DIABLO 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 DIABLO 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)
- CA0710007
- System type
- Community Water System
- Population served
- 43,357
- Service connections
- 13,617
- Ownership
- local government
- Water source
- surface water (rivers, lakes, or reservoirs)
DIABLO WATER DISTRICT is one of 376 community water systems in California in the 10,001 to 100,000 people size category, serving 43,357 people from surface water.
As of August 1, 2026, EPA's published records contain no violations for this system.
Violation history
No violations on record for this system.
Enforcement actions
No enforcement actions on record for this system.
Common questions
Is DIABLO WATER DISTRICT required to publish a Consumer Confidence Report?
- Yes. DIABLO 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 DIABLO WATER DISTRICT’s next Consumer Confidence Report due?
- DIABLO WATER DISTRICT’s next Consumer Confidence Report is due by July 1, 2027. The report covers calendar year 2026.
Does DIABLO WATER DISTRICT have any open drinking water violations on record?
- As of August 1, 2026, EPA's federal records show no open violations for DIABLO 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
MUELRATH, DAN
925-625-3798
OAKLEY, CA 94561