Is there PFAS in City of Tempe water?
Yes. EPA's final UCMR 5 results show City of Tempe averaged 55.2 ppt of PFOS at its worst sampling point, 13.8 times the EPA limit of 4 ppt.
City of Tempe
Serves 165,000 people · 24 PFOA samples from 10 sampling points · Jul 2023 to Mar 2025
Average above an EPA limit
PFOA Perfluorooctanoic acid
37.9 ppt avg · max 38.7
PFOS Perfluorooctanesulfonic acid
55.2 ppt avg · max 55.8
PFHxS Perfluorohexanesulfonic acid
67.8 ppt avg · max 70.5
Hazard index GenX, PFBS, PFNA, PFHxS combined
6.8 avg · max 7.1
Also detected, no federal limit: PFBS, PFHxA, PFPeA, PFBA, PFPeS, PFHpA.
City of Tempe is a public water system drawing on surface water, based in Tempe, Arizona, serving about 165,000 people. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 24 times across 10 sampling points between Jul 2023 and Mar 2025.
Every PFAS detected
Not detected: PFUnA, PFDoA, PFDA, PFNA, PFTrDA, NEtFOSAA, PFTA, PFMBA, NMeFOSAA, 6:2 FTS, 4:2 FTS, 8:2 FTS, 11Cl-PF3OUdS, PFEESA, NFDHA, PFHpS, HFPO-DA, ADONA, 9Cl-PF3ONS, PFMPA.
Lithium, tested in the same program: highest 278 ppb, detected in 24 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 Arizona
All 152 tested systems in Arizona
ZIP codes served
85280 85281 85282 85283 85284 85288
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 Tempe water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID AZ0407100. https://wellandtap.com/pfas/arizona/city-of-tempe/
About this data
Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID AZ0407100). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.
