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California tap water

State answer

127 of 657 California water systems with full PFAS testing (19%) averaged above a 2024 federal PFAS level at one or more sampling points.

Largest systems

SystemPeople servedPFAS above a 2024 level?Health-based violations since 2021-10-26
Los Angeles-City, dept. of Water & Power3,875,566No0
East Bay Mud1,468,000No0
San Diego, City of1,408,937No0
San Jose Water1,039,920No1
Sfpuc City Distribution Division848,019No0
Eastern Municipal Wd659,923No0
City of Fresno545,970Yes, at one or more sampling points0
City of Sacramento Main527,979Yes, at one or more sampling points0

Counties

Los Angeles County109 systems with full PFAS testingSan Bernardino County44 systems with full PFAS testingRiverside County29 systems with full PFAS testingOrange County29 systems with full PFAS testingSacramento County27 systems with full PFAS testingKern County25 systems with full PFAS testingSan Diego County22 systems with full PFAS testingVentura County20 systems with full PFAS testingFresno County17 systems with full PFAS testingSanta Clara County15 systems with full PFAS testingSanta Barbara County15 systems with full PFAS testingSan Mateo County15 systems with full PFAS testingSan Luis Obispo County15 systems with full PFAS testingSonoma County13 systems with full PFAS testingStanislaus County12 systems with full PFAS testingMonterey County12 systems with full PFAS testingSan Joaquin County11 systems with full PFAS testingTulare County11 systems with full PFAS testingMerced County11 systems with full PFAS testing

All 207 utilities with a page in California

Why not "the state's water quality"? You drink from one utility, not a state. Rollups count systems, not people, so one large utility counts the same as a small one. Use the system pages for your actual water.

Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.

Sources and freshness

Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.