Is there PFAS in City of Stockton water?
Yes. EPA's final UCMR 5 results show City of Stockton averaged 14.0 ppt of PFOS at its worst sampling point, 3.5 times the EPA limit of 4 ppt.
City of Stockton
Serves 191,302 people · 38 PFOA samples from 17 sampling points · Feb 2023 to Dec 2025
Average above an EPA limit
PFOA Perfluorooctanoic acid
3.4 ppt avg · max 6.7
PFOS Perfluorooctanesulfonic acid
14.0 ppt avg · max 28.0
Hazard index GenX, PFBS, PFNA, PFHxS combined
not detected
Also detected, no federal limit: PFBS.
City of Stockton is a public water system drawing on surface water, based in Stockton, California, serving about 191,302 people, including Stockton, French Camp. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 38 times across 17 sampling points between Feb 2023 and Dec 2025.
Every PFAS detected
Not detected: PFDA, NFDHA, PFHpS, PFPeS, PFHpA, PFTA, PFTrDA, NEtFOSAA, NMeFOSAA, PFPeA, PFHxA, PFEESA, PFHxS, PFNA, HFPO-DA, PFMBA, 4:2 FTS, PFBA, 8:2 FTS, ADONA, 9Cl-PF3ONS, 11Cl-PF3OUdS, PFUnA, PFMPA, PFDoA, 6:2 FTS.
Lithium, tested in the same program: not detected.
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
All 707 tested systems in California
ZIP codes served
95205 95206 95207 95209 95210 95212 95215 95219 95231
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 City of Stockton water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID CA3910012. https://wellandtap.com/pfas/california/city-of-stockton/
About this data
Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID CA3910012). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.
