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Is there PFAS in Cws - Bakersfield water?

Yes. EPA's final UCMR 5 results show Cws - Bakersfield averaged 13.5 ppt of PFOS at its worst sampling point, 3.4 times the EPA limit of 4 ppt.

Cws - Bakersfield Serves 267,881 people · 98 PFOA samples from 47 sampling points · Jul 2023 to Apr 2026 Average above an EPA limit
PFOA Perfluorooctanoic acid 4.5 ppt avg · max 9.1
EPA 4
PFOS Perfluorooctanesulfonic acid 13.5 ppt avg · max 14.0
EPA 4
PFHxS Perfluorohexanesulfonic acid 6.7 ppt avg · max 7.3
EPA 10
Hazard index GenX, PFBS, PFNA, PFHxS combined 0.7 avg · max 0.7
EPA 1

Also detected, no federal limit: PFBS, PFPeA, PFHxA, PFHpA.

Averages are for the worst sampling point, with non-detects counted as zero. Source: EPA UCMR 5.

Cws - Bakersfield is a public water system drawing on surface water, based in San Jose, California, serving about 267,881 people. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 98 times across 47 sampling points between Jul 2023 and Apr 2026.

Every PFAS detected

PFAS Detected Highest Worst point avg EPA limit
PFOS
Perfluorooctanesulfonic acid		 19 of 98 14.0 ppt 13.5 ppt 4 ppt
PFOA
Perfluorooctanoic acid		 3 of 98 9.1 ppt 4.5 ppt 4 ppt
PFHxS
Perfluorohexanesulfonic acid		 10 of 98 7.3 ppt 6.7 ppt 10 ppt
PFBS
Perfluorobutanesulfonic acid		 2 of 98 6.6 ppt 4.8 ppt none
PFPeA
Perfluoropentanoic acid		 9 of 98 5.5 ppt 5.3 ppt none
PFHxA
Perfluorohexanoic acid		 3 of 98 4.6 ppt 2.3 ppt none
PFHpA
Perfluoroheptanoic acid		 1 of 98 3.5 ppt 1.8 ppt none

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

Lithium, tested in the same program: highest 14.6 ppb, detected in 22 of 98 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

All 707 tested systems in California

ZIP codes served

93301 93304 93305 93306 93307 93308 93309 93311 93313 93314

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 Cws - Bakersfield water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID CA1510003. https://wellandtap.com/pfas/california/cws-bakersfield/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID CA1510003). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.