Is there PFAS in California Water Service - Livermore water?

Yes. EPA's final UCMR 5 results show California Water Service - Livermore averaged 10.4 ppt of PFOS at its worst sampling point, 2.6 times the EPA limit of 4 ppt.

California Water Service - Livermore is a public water system drawing on surface water, based in San Jose, California, serving about 60,414 people, including Livermore, Pleasanton. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 24 times across 8 sampling points between Jul 2023 and Jul 2024.

Every PFAS detected

Not detected: PFTA, PFDoA, PFDA, PFNA, PFHpA, NMeFOSAA, PFTrDA, 4:2 FTS, NEtFOSAA, PFBA, PFUnA, PFPeS, NFDHA, PFMBA, PFMPA, 8:2 FTS, ADONA, 11Cl-PF3OUdS, PFEESA, 9Cl-PF3ONS, PFHpS, HFPO-DA, 6:2 FTS.

Lithium, tested in the same program: highest 25.1 ppb, detected in 11 of 24 samples. EPA's health-based screening level is 10 ppb.

What the EPA limits mean here

In April 2024 EPA set enforceable limits of 4 ppt for PFOA and PFOS, 10 ppt each for PFHxS, PFNA and GenX, and a hazard index of 1 for mixtures. Utilities were given until 2029 to comply. In May 2026 EPA proposed keeping only the PFOA and PFOS limits and moving that deadline to 2031. Until that proposal is final, the 2024 limits stand.

Compliance is judged on a running annual average at each entry point, so we show the average at this system's worst sampling point next to its single highest result. UCMR 5 results do not by themselves put a utility in or out of compliance.

What you can do at home

Two routes work for PFAS. For drinking and cooking water only, a reverse osmosis system certified to NSF/ANSI 58 with a PFOA/PFOS reduction claim is the cheapest proven option. To treat every tap and shower, a whole-house carbon system with enough contact time works, but check that the maker has PFAS test data, not just a marketing claim. See the best filters for PFAS and how PFAS removal works.

Other systems in California

• City of Petaluma none detected
• California Water Service - Bear Gulch none detected
• City of Woodland none detected
• City of Gilroy above an EPA limit
• North Marin Water District none detected
• City of Hanford none detected

All 707 tested systems in California

ZIP codes served

94550 94551 94566

As reported by the utility to EPA. Neighbouring ZIPs are often split between systems; your water bill names yours.

Cite this page

Well & Tap. "PFAS in California Water Service - Livermore water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID CA0110003. https://wellandtap.com/pfas/california/california-water-service-livermore/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID CA0110003). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.