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Is there PFAS in Zapata County Waterworks Swtp water?

Yes, at low levels. 1 PFAS was detected, all below EPA's 2024 limits.

Zapata County Waterworks Swtp Serves 13,736 people · 3 PFOA samples from 1 sampling point · Aug 2025 to May 2026 PFAS found, below EPA limits
PFOA Perfluorooctanoic acid not detected
EPA 4
PFOS Perfluorooctanesulfonic acid not detected
EPA 4

Also detected, no federal limit: PFPeA.

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

Zapata County Waterworks Swtp is a public water system drawing on surface water, based in Zapata, Texas, serving about 13,736 people. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 3 times across 1 sampling point between Aug 2025 and May 2026.

Every PFAS detected

PFAS Detected Highest Worst point avg EPA limit
PFPeA
Perfluoropentanoic acid
1 of 3 3.2 ppt 1.1 ppt none

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

Lithium, tested in the same program: highest 30.9 ppb, detected in 4 of 4 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 Texas

All 1154 tested systems in Texas

ZIP codes served

78076

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 Zapata County Waterworks Swtp water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID TX2530002. https://wellandtap.com/pfas/texas/zapata-county-waterworks-swtp/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID TX2530002). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.