EPA EXPORT · 13 SEP 2026FEDERAL COMPLIANCE RECORDS · NOT A HOME WATER TEST
TAP WATERLEDGERPublic system compliance records

COUNTY WATER-SYSTEM LEDGER

Contra Costa, California

Compare active community water systems serving this county in EPA's public export. Systems can serve multiple places, so population totals may overlap.

Systems8active CWS · pop. 2,500+
Population served554,962reported total; may overlap
Current violation flag0.0%0 systems
Serious-violator flag0.0%0 systems

01 / SYSTEMS

Water systems serving Contra Costa

Ordered by reported population served. Open any record for separate health, monitoring, notice, other, and serious-violator flags.

Water systemPopulation servedPrimary sourceCurrent export status
Contra Costa Water DistrictCA0710003198,000Surface waterNo current violation flagged
City Of AntiochCA0710001115,074Surface waterNo current violation flagged
BrentwoodCA071000464,513Surface water purchasedNo current violation flagged
City Of PittsburgCA071000862,500Surface water purchasedNo current violation flagged
Diablo Water DistrictCA071000743,357Surface water purchasedNo current violation flagged
City Of MartinezCA071000630,997Surface water purchasedNo current violation flagged
Golden State Water Company - Bay PointCA071000223,731Surface water purchasedNo current violation flagged
Town Of Discovery BayCA071000916,790Ground waterNo current violation flagged

02 / SOURCE MIX

Surface water2 systems · 313,074 served
Surface water purchased5 systems · 225,098 served
Ground water1 systems · 16,790 served
How to read the population total

It is the sum of each listed system's reported population served, not a census estimate. Service areas can overlap and some systems list multiple cities or counties.