Well & TapHome Water Treatment Database

Is there PFAS in Mayaguez water?

No PFAS were detected in any of the 26 samples EPA's program collected.

Mayaguez Serves 152,342 people · 26 PFOA samples from 12 sampling points · Mar 2025 to Dec 2025 No PFAS detected
PFOA Perfluorooctanoic acid not detected
EPA 4
PFOS Perfluorooctanesulfonic acid not detected
EPA 4
Averages are for the worst sampling point, with non-detects counted as zero. Source: EPA UCMR 5.

Mayaguez is a public water system drawing on surface water, based in Mayaguez, Puerto Rico, serving about 152,342 people. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 26 times across 12 sampling points between Mar 2025 and Dec 2025.

Every PFAS detected

None of the 29 PFAS were found at or above EPA's minimum reporting levels (2 to 20 ppt depending on the compound).

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

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

No PFAS action is needed on these results. If your water tastes or smells of chlorine, a whole-house city water filter is the usual fix.

Other systems in Puerto Rico

All 99 tested systems in Puerto Rico

ZIP codes served

00680

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 Mayaguez water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID PR0003283. https://wellandtap.com/pfas/puerto-rico/mayaguez/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID PR0003283). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.