Is there PFAS in City of Mesa water?
Yes, at low levels. 3 PFAS were detected, all below EPA's 2024 limits.
City of Mesa
Serves 466,000 people · 70 PFOA samples from 31 sampling points · Feb 2023 to Nov 2025
PFAS found, below EPA limits
PFOA Perfluorooctanoic acid
not detected
PFOS Perfluorooctanesulfonic acid
not detected
PFHxS Perfluorohexanesulfonic acid
8.9 ppt avg · max 9.3
Hazard index GenX, PFBS, PFNA, PFHxS combined
0.9 avg · max 0.9
Also detected, no federal limit: PFBS, PFHxA.
City of Mesa is a public water system drawing on surface water, based in Mesa, Arizona, serving about 466,000 people, including Mesa, Gilbert. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 70 times across 31 sampling points between Feb 2023 and Nov 2025.
Every PFAS detected
Not detected: ADONA, PFTrDA, PFTA, PFHpA, PFNA, PFOS, PFOA, PFDA, PFDoA, PFUnA, PFPeS, 9Cl-PF3ONS, NMeFOSAA, HFPO-DA, PFBA, 6:2 FTS, 4:2 FTS, PFHpS, 8:2 FTS, PFMPA, PFPeA, PFMBA, PFEESA, NFDHA, 11Cl-PF3OUdS, NEtFOSAA.
Lithium, tested in the same program: highest 525 ppb, detected in 70 of 70 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
Levels here are under EPA's limits, so no treatment is required. If you want them lower anyway, a certified reverse osmosis system under the sink handles drinking water, and a whole-house carbon filter also takes out the chlorine or chloramine your utility adds.
Other systems in Arizona
All 152 tested systems in Arizona
ZIP codes served
85201 85202 85203 85204 85205 85206 85207 85208 85209 85210 85211 85212 85213 85214 85215 85234
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 Mesa water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID AZ0407095. https://wellandtap.com/pfas/arizona/city-of-mesa/
About this data
Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID AZ0407095). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.
