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Is there PFAS in Regional Water Authority water?

Some. At least one sample reached an EPA limit, but the average at every sampling point stayed below it.

Regional Water Authority Serves 418,900 people · 30 PFOA samples from 1 sampling point · Sep 2023 to Jun 2024 One or more samples at an EPA limit
PFOA Perfluorooctanoic acid 0.8 ppt avg · max 7.1
EPA 4
PFOS Perfluorooctanesulfonic acid 1.3 ppt avg · max 10.7
EPA 4
Hazard index GenX, PFBS, PFNA, PFHxS combined not detected
EPA 1

Also detected, no federal limit: PFBS, PFPeA.

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

Regional Water Authority is a public water system drawing on surface water, based in New Haven, Connecticut, serving about 418,900 people, including Ansonia, Branford, Cheshire, Derby, Milford, Milldale. Under EPA's Fifth Unregulated Contaminant Monitoring Rule it was tested for 29 PFAS and lithium 30 times across 1 sampling point between Sep 2023 and Jun 2024.

Every PFAS detected

PFAS Detected Highest Worst point avg EPA limit
PFOS
Perfluorooctanesulfonic acid		 7 of 30 10.7 ppt 1.3 ppt 4 ppt
PFOA
Perfluorooctanoic acid		 4 of 30 7.1 ppt 0.8 ppt 4 ppt
PFBS
Perfluorobutanesulfonic acid		 3 of 30 3.5 ppt 0.3 ppt none
PFPeA
Perfluoropentanoic acid		 1 of 30 3.1 ppt 0.1 ppt none

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

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

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 Connecticut

All 63 tested systems in Connecticut

ZIP codes served

06401 06405 06408 06411 06418 06460 06461 06467 06471 06472 06473 06477 06483 06501 06502 06503 06504 06505 06506 06507 06508 06509 06510 06511 06512 06513 06514 06515 06516 06517 06518 06519 06520 06521 06524 06525 06530 06531 06532 06533 06534 06535 06536 06537 06538 06540 06716

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 Regional Water Authority water: EPA UCMR 5 results." Data: U.S. EPA Fifth Unregulated Contaminant Monitoring Rule, final release August 2026, PWSID CT0930011. https://wellandtap.com/pfas/connecticut/regional-water-authority/

About this data

Source: U.S. EPA, UCMR 5 occurrence data, final release August 2026 (PWSID CT0930011). Population: EPA SDWIS. Averages count results below the reporting level as zero, the same convention EPA uses for running annual averages. Full method.