California tap water by county

Hardness, PFAS sampling, lead and violations for the largest water systems in 22 California counties. In 20 of them, at least one large system detected PFAS in EPA testing (a detection isn't a violation).

CountyLargest systemHardnessPFAS detected
Los Angeles CountyLos Angeles-City, Dept. of Water & Power6.0 gpg (high)2 of 6 systems
San Diego CountySan Diego, City of200–285 mg/L (varies) (high)1 of 6 systems
Orange CountyCity of Anaheim135–431 mg/L (varies) (high)5 of 6 systems
Riverside CountyEastern Municipal WD12.6 gpg (low)4 of 6 systems
San Bernardino CountySan Bernardino City8.9 gpg (low)2 of 5 systems
Santa Clara CountySan Jose Water77–451 mg/L (varies) (high)2 of 6 systems
Alameda CountyEast Bay MUD17.1–153.9 mg/L (varies) (high)3 of 6 systems
Sacramento CountyCity of Sacramento Main15–154 mg/L (varies) (high)4 of 6 systems
Contra Costa CountyContra Costa Water District9.3 gpg (low)0 of 6 systems
Fresno CountyCity of Fresno7.5 gpg (high)3 of 6 systems
Kern CountyCws - Bakersfield7.0 gpg (low)2 of 6 systems
Ventura CountyOxnard Water Dept27.5 gpg (low)1 of 6 systems
San Francisco CountySfpuc City Distribution Division3.6 gpg (high)1 of 3 systems
San Joaquin CountyCity of Stockton7.6 gpg (low)5 of 6 systems
San Mateo CountyCity of Daly City3.8 gpg (low)0 of 6 systems
Stanislaus CountyModesto, City of13.4 gpg (low)2 of 6 systems
Sonoma CountySanta Rosa, City of6.8 gpg (low)3 of 6 systems
Tulare CountyCws - Visalia1.8 gpg (low)3 of 6 systems
Solano CountyCity of Vallejo15.2 gpg (low)2 of 6 systems
Santa Barbara CountyCity of Santa Maria Utilities Department29.6 gpg (low)1 of 6 systems
Monterey CountyCal Am Water Company - Monterey12.9 gpg (low)1 of 6 systems
Placer CountyCity of Roseville2.0 gpg (low)1 of 6 systems

Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.

Hardness confidence: high = utility report; low = county estimate of untreated local water. Don't see your county? Use the water quality lookup.