PFAS above EPA’s limits in Connecticut.
The short answer
29 utilities serving 1.2 million people, as they report it, had a location averaging above a limit, most often PFOA (25) and PFOS (21). The largest is Regional Water Authority, whose highest PFOS average was 9.4 ppt, 2.4 times the limit. The furthest above is Manchester Water Department, at 4 times the PFOS limit.
These are EPA’s survey results, not violations: the limits take effect April 26, 2029, and compliance will rest on each utility’s own monitoring. EPA has proposed changes to the rule; as of Oct. 13, 2026, none is final.
Utilities above a limit
Largest first. Each one’s highest location average is for the limit it is furthest above, with the single highest sample of the same PFAS; its report has every result.
| Utility | Based in | Serves | Above | Highest location average | Highest single sample |
|---|---|---|---|---|---|
| Regional Water Authority | Ansonia | 418,900 | PFOA, PFOS | PFOS 9.4 ppt2.4 times the limit | 11 ppt |
| Ctwc - Northern Reg - Western System | East Granby | 101,313 | PFOA, PFOS | PFOA 6.5 ppt1.6 times the limit | 8.0 ppt |
| Danbury Water Department | Bethel | 62,055 | PFOA | PFOA 4.5 ppt1.1 times the limit | 5.4 ppt |
| Meriden Water Division | Berlin | 58,441 | PFOS | PFOS 7.7 ppt1.9 times the limit | 9.5 ppt |
| Aquarion - Greenwich | Greenwich | 53,297 | PFOA | PFOA 4.9 ppt1.2 times the limit | 5.6 ppt |
| Bristol Water Department | Bristol | 52,079 | PFOA | PFOA 4.1 ppt1.02 times the limit | 4.1 ppt |
| Manchester Water Department | Glastonbury | 51,198 | PFOA, PFOS | PFOS 16 ppt4 times the limit | 16 ppt |
| Southington Water Department | Cheshire | 43,069 | PFOA, PFOS | PFOA 7.5 ppt1.9 times the limit | 8.0 ppt |
| Norwalk First Taxing District | New Canaan | 40,256 | PFOA, PFOS | PFOS 10 ppt2.5 times the limit | 11 ppt |
| Wallingford Water Department | North Haven | 37,267 | PFOS | PFOS 12 ppt3.1 times the limit | 14 ppt |
| Norwich Public Utilities | Franklin | 36,163 | PFOA, PFOS | PFOS 15 ppt3.8 times the limit | 16 ppt |
| Ctwc - Shoreline Region - Guilford System | Clinton | 33,975 | PFOA, PFOS | PFOS 8.0 ppttwice the limit | 12 ppt |
| University of Connecticut - Main Campus | Mansfield | 27,199 | PFOS | PFOS 4.5 ppt1.1 times the limit | 5.0 ppt |
| Mashantucket Pequot Water System | Mashantucket | 22,171 | PFOA | PFOA 5.3 ppt1.3 times the limit | 7.4 ppt |
| Hazardville Water Company | East Windsor | 18,544 | PFOA, PFOS | PFOA 7.7 ppt1.9 times the limit | 8.6 ppt |
| Aquarion - Plainville Regional | Bristol | 18,231 | PFOA, PFOS | PFOS 6.5 ppt1.6 times the limit | 6.8 ppt |
| East Lyme Water & Sewer Commission | East Lyme | 15,245 | PFOA, PFOS | PFOA 8.6 ppt2.1 times the limit | 9.2 ppt |
| Ctwc - Unionville System | Avon | 14,693 | PFOA, PFOS | PFOS 5.5 ppt1.4 times the limit | 6.0 ppt |
| Aquarion - New Milford Regional | Brookfield | 13,331 | PFOA | PFOA 5.0 ppt1.3 times the limit | 5.3 ppt |
| Aquarion - Valley | Ansonia | 13,080 | PFOA | PFOA 5.3 ppt1.3 times the limit | 8.1 ppt |
| Avon Water Co | Avon | 11,590 | PFOA, PFOS | PFOS 8.0 ppttwice the limit | 8.0 ppt |
| Bethel Water Dept | Bethel | 9,507 | PFOA | PFOA 5.7 ppt1.4 times the limit | 5.9 ppt |
| Aquarion - Ridgefield | Ridgefield | 7,476 | PFOA, PFOS | PFOA 8.7 ppt2.2 times the limit | 11 ppt |
| Putnam Water Pollution Control Authority | Putnam | 7,300 | PFOA | PFOA 7.5 ppt1.9 times the limit | 8.5 ppt |
| Ctwc - Crystal System | Brooklyn | 6,378 | PFOA, PFOS | PFOA 9.4 ppt2.4 times the limit | 9.9 ppt |
| Ctwc - Naugatuck Reg - Collinsville Sys | Avon | 6,324 | PFOA, PFOS | PFOS 5.4 ppt1.4 times the limit | 5.6 ppt |
| Aquarion - Newtown Regional | Newtown | 6,054 | PFOA, PFOS | PFOA 13 ppt3.2 times the limit | 16 ppt |
| Colchester Sewer & Water Commission | Colchester | 4,020 | PFOS | PFOS 8.1 ppttwice the limit | 9.0 ppt |
| Aquarion - Woodrich Village | Wolcott | 72 | PFOA, PFOS | PFOA 5.6 ppt1.4 times the limit | 6.3 ppt |
7 more utilities in Connecticut had a single sample above a limit but no location average above, so they are not listed; each report shows the sample.
Results: EPA UCMR 5 occurrence data, file of Oct. 15, 2026, samples from Jan. 3, 2023 to June 17, 2026, averaged by sampling location as EPA’s final UCMR 5 data summary does. Every state, and the full data as a CSV; how this list is made. People served is what each utility reports.
Where to go next
- Regional Water Authority’s reportEvery PFAS result with its dates, and the certification claim that handles each.Open the report
- Every stateThe national list, the largest utilities above a limit, and the data to download.PFAS above EPA’s limits
- Filters certified for PFASRanked by certification and what they cost over five years.Best water filters for PFAS