SAN JOSE, CA · San Mateo County
CALIFORNIA WATER SERVICE - SAN MATEO Water System
Consumer Confidence Report status
CALIFORNIA WATER SERVICE - SAN MATEO 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 CALIFORNIA WATER SERVICE - SAN MATEO.
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)
- CA4110008
- System type
- Community Water System
- Population served
- 102,348
- Service connections
- 25,440
- Ownership
- privately owned
- Water source
- surface water (rivers, lakes, or reservoirs)
CALIFORNIA WATER SERVICE - SAN MATEO is one of 92 community water systems in California in the more than 100,000 people size category, serving 102,348 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
- January 25, 2019State Compliance achieved21 linked violations
Common questions
Is CALIFORNIA WATER SERVICE - SAN MATEO required to publish a Consumer Confidence Report?
- Yes. CALIFORNIA WATER SERVICE - SAN MATEO 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 CALIFORNIA WATER SERVICE - SAN MATEO’s next Consumer Confidence Report due?
- CALIFORNIA WATER SERVICE - SAN MATEO’s next Consumer Confidence Report is due by July 1, 2027. The report covers calendar year 2026.
Does CALIFORNIA WATER SERVICE - SAN MATEO have any open drinking water violations on record?
- As of August 1, 2026, EPA's federal records show no open violations for CALIFORNIA WATER SERVICE - SAN MATEO.
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
JAMES, SOPHIE
408-367-8593
SAN JOSE, CA 95112