PFAS · Connecticut
PFAS in Connecticut drinking water: EPA’s final survey results
EPA’s national PFAS survey (UCMR 5) tested 62 of the community water systems that serve homes in Connecticut. 41 found at least one of 29 PFAS above the laboratory reporting level, and 29 had a PFOA or PFOS sampling-location yearly average at or above EPA’s 4.0 ppt limit. Samples were collected from January 2023 to April 2026.
Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages
PFOA was the compound Connecticut community systems found most often: 32 of 62 tested systems measured it above the reporting level. Across the country, 35% of surveyed community systems found at least one PFAS; in Connecticut the share is 66%. The largest Connecticut system with a detection, Regional Water Authority, serves 418,900 people and found 4 of the 29 compounds.
Which PFAS were found most often in Connecticut
Each row counts the Connecticut community water systems where that compound was measured above the reporting level at least once. A detection is a measurement, not a violation: most of these compounds have no federal limit.
| Compound | Systems where found | Systems tested | Share |
|---|---|---|---|
| PFOA | 32 | 62 | 52% |
| PFOS | 28 | 62 | 45% |
| PFPeA | 27 | 62 | 44% |
| PFBS | 25 | 62 | 40% |
| PFHxA | 24 | 62 | 39% |
| PFHxS | 16 | 62 | 26% |
| PFBA | 13 | 62 | 21% |
| PFHpA | 8 | 62 | 13% |
| ADONA | 1 | 62 | 2% |
Connecticut systems with the most PFAS found
The 10 surveyed community water systems that found the most different PFAS, with PFOA and PFOS compared to EPA’s 4.0 ppt limits on the yearly average at the highest sampling location. Larger systems come first when counts tie.
| Water system | People served | PFAS found (of 29) | PFOA | PFOS |
|---|---|---|---|---|
| Aquarion-Newtown Regional CT0970011 | 6,054 | 8 | 12.7 ppt at or above the MCL | 12.1 ppt at or above the MCL |
| Aquarion-Eastern Fairfield County CT0150011 | 351,756 | 7 | 1.1 ppt below the MCL | 0.0 ppt below the MCL |
| Ctwc - Northern Reg-Western System CT0473011 | 101,313 | 7 | 6.5 ppt at or above the MCL | 5.5 ppt at or above the MCL |
| Meriden Water Division CT0800011 | 58,441 | 7 | 2.3 ppt below the MCL | 7.7 ppt at or above the MCL |
| Manchester Water Department CT0770021 | 51,198 | 7 | 12.5 ppt at or above the MCL | 16.0 ppt at or above the MCL |
| Southington Water Department CT1310011 | 43,069 | 7 | 7.5 ppt at or above the MCL | 5.5 ppt at or above the MCL |
| Ctwc - Shoreline Region-Guilford System CT0608011 | 33,975 | 7 | 6.0 ppt at or above the MCL | 8.0 ppt at or above the MCL |
| Aquarion-Ridgefield CT1180011 | 7,476 | 7 | 8.7 ppt at or above the MCL | 5.8 ppt at or above the MCL |
| Norwalk First Taxing District CT1030011 | 40,256 | 6 | 8.7 ppt at or above the MCL | 10.1 ppt at or above the MCL |
| Mashantucket Pequot Water System 010106001 | 22,171 | 6 | 5.3 ppt at or above the MCL | — not detected above the reporting level |
Counties with the most systems that found PFAS
- Hartford County 11 of 14 surveyed systems
- Fairfield County 11 of 12 surveyed systems
- New Haven County 7 of 9 surveyed systems
- New London County 5 of 8 surveyed systems
- Windham County 3 of 3 surveyed systems
- Middlesex County 2 of 4 surveyed systems
- Litchfield County 1 of 9 surveyed systems
- Tolland County 1 of 2 surveyed systems