Results from entry points (water leaving treatment, not household taps) of public water systems sampled under EPA's Fifth Unregulated Contaminant Monitoring Rule. Click a county to see every water system serving it, or turn on service areas and click a location to see the systems that serve that spot.
65 of the 952 public water systems listed for Connecticut were sampled. Sorted by the highest single result relative to EPA's 2024 limits. Each name links to a page with all of that system's results. All 952 Connecticut systems, including those not tested · Download all Connecticut results (CSV, gzip)
| System | PWSID | City | Population | PFOA (ppt) | PFOS (ppt) | HI | Highest single result |
|---|---|---|---|---|---|---|---|
| Norwich Public Utilities | CT1040011 | Norwich | 36,163 | 6.7 | 16.2 | 1.253 | PFOS ≥ 3 × its limit |
| Manchester Water Department | CT0770021 | Manchester | 51,198 | 13 | 16 | 0.383 | PFOS ≥ 3 × its limit |
| Aquarion-Newtown Regional | CT0970011 | Shelton | 6,054 | 15.9 | 12.7 | 0.493 | PFOA ≥ 3 × its limit |
| Wallingford Water Department | CT1480011 | Wallingford | 37,267 | <MRL | 13.9 | 1.072 | PFOS ≥ 3 × its limit |
| Ctwc - Shoreline Region-Guilford System | CT0608011 | Clinton | 33,975 | 6 | 12 | 0.4 | PFOS ≥ 3 × its limit |
| Norwalk First Taxing District | CT1030011 | Norwalk | 40,256 | 9.5 | 11.2 | 0.423 | PFOS 1–3 × its limit |
| Aquarion-Eastern Fairfield County | CT0150011 | Shelton | 351,756 | 10.9 | 6.6 | 0.002 | PFOA 1–3 × its limit |
| Regional Water Authority | CT0930011 | New Haven | 418,900 | 7.1 | 10.7 | 0.002 | PFOS 1–3 × its limit |
| Aquarion-Ridgefield | CT1180011 | Shelton | 7,476 | 10.6 | 6.1 | 0.002 | PFOA 1–3 × its limit |
| Ctwc - Crystal System | CT0690011 | Clinton | 6,378 | 9.9 | 6.8 | 0.4 | PFOA 1–3 × its limit |
| Meriden Water Division | CT0800011 | Meriden | 58,441 | 6.1 | 9.5 | 0.402 | PFOS 1–3 × its limit |
| East Lyme Water & Sewer Commission | CT0450011 | Niantic | 15,245 | 9.2 | 7.2 | 0.002 | PFOA 1–3 × its limit |
| Colchester Sewer & Water Commission | CT0280011 | Colchester | 4,020 | <MRL | 9 | 0.36 | PFOS 1–3 × its limit |
| Hazardville Water Company | CT0490021 | Enfield | 18,544 | 8.6 | 5.4 | 0.812 | PFOA 1–3 × its limit |
| Putnam Water Pollution Control Authority | CT1160011 | Putnam | 7,300 | 8.5 | 7.5 | 0.4 | PFOA 1–3 × its limit |
| Aquarion-Valley | CT1240011 | Shelton | 13,080 | 8.1 | 6.9 | 0.002 | PFOA 1–3 × its limit |
| Avon Water Co | CT0040011 | Clinton | 11,590 | 7 | 8 | 0.002 | PFOS 1–3 × its limit |
| Ctwc - Northern Reg-Western System | CT0473011 | Clinton | 101,313 | 8 | 6 | 0.301 | PFOA 1–3 × its limit |
| Southington Water Department | CT1310011 | Southington | 43,069 | 8 | 6 | 0.002 | PFOA 1–3 × its limit |
| Mashantucket Pequot Water System | 010106001 | Mashantucket | 22,171 | 7.4 | <MRL | 0.002 | PFOA 1–3 × its limit |
| Aquarion-Plainville Regional | CT1100011 | Shelton | 18,231 | 5.2 | 6.8 | 0 | PFOS 1–3 × its limit |
| Aquarion-Woodrich Village | CT1666011 | Shelton | 72 | 6.3 | 6.2 | 0.002 | PFOA 1–3 × its limit |
| Ctwc - Unionville System | CT0520011 | Clinton | 14,693 | 6 | 6 | 0.3 | PFOA 1–3 × its limit |
| Bethel Water Dept | CT0090011 | Bethel | 9,507 | 5.9 | <MRL | 0.002 | PFOA 1–3 × its limit |
| Aquarion-Darien | CT0350011 | Shelton | 18,737 | 5.8 | <MRL | 0 | PFOA 1–3 × its limit |
| Aquarion-Greenwich | CT0570011 | Shelton | 53,297 | 5.6 | 4.1 | 0 | PFOA 1–3 × its limit |
| Aquarion-New Canaan | CT0900011 | Shelton | 10,097 | 5.6 | <MRL | 0 | PFOA 1–3 × its limit |
| Ctwc - Naugatuck Reg-Collinsville Sys | CT0230011 | Clinton | 6,324 | 4.9 | 5.6 | 0 | PFOS 1–3 × its limit |
| Danbury Water Department | CT0340011 | Danbury | 62,055 | 5.4 | <MRL | 0.002 | PFOA 1–3 × its limit |
| Aquarion-New Milford Regional | CT0960011 | Shelton | 13,331 | 5.3 | 5.3 | 0.003 | PFOA 1–3 × its limit |
| University Of Connecticut - Main Campus | CT0780021 | Storrs | 27,199 | <MRL | 5 | 0 | PFOS 1–3 × its limit |
| Cromwell Fire District Water Department | CT0330011 | Cromwell | 14,316 | <MRL | 4.6 | 0.87 | PFOS 1–3 × its limit |
| Aquarion-Simsbury Regional | CT1280021 | Shelton | 14,691 | 4.4 | 4.3 | 0.37 | PFOA 1–3 × its limit |
| Aquarion-Stamford | CT1350011 | Shelton | 119,214 | 4.3 | <MRL | 0 | PFOA 1–3 × its limit |
| Bristol Water Department | CT0170011 | Bristol | 52,079 | 4.1 | <MRL | 0 | PFOA 1–3 × its limit |
| Heritage Water Company | CT1300021 | Clinton | 7,300 | 4.1 | <MRL | 0.002 | PFOA 1–3 × its limit |
| Berlin Water Control Commission | CT0070021 | Berlin | 5,128 | <MRL | <MRL | 0.38 | Hazard Index below its limit |
| Aquarion-Mystic | CT1370011 | Shelton | 10,788 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Jewett City Water Company | CT0580011 | Enfield | 6,840 | <MRL | <MRL | 0 | Other PFAS detected |
| Portland Water Department | CT1130011 | Portland | 5,010 | <MRL | <MRL | 0 | Other PFAS detected |
| Windham Water Works | CT1630011 | Mansfield Center | 21,214 | <MRL | <MRL | 0 | Other PFAS detected |
| Aquarion-Litchfield Regional | CT0740011 | Shelton | 3,097 | <MRL | <MRL | 0 | No PFAS detected |
| Aquarion-New Hartford | CT0920011 | Shelton | 1,872 | <MRL | <MRL | 0 | No PFAS detected |
| Ctwc - Coventry Hills Div | CT0320091 | Clinton | 700 | <MRL | <MRL | 0 | No PFAS detected |
| Ctwc - Naugatuck Reg-Terryville System | CT1110011 | Clinton | 5,607 | <MRL | <MRL | 0 | No PFAS detected |
| Ctwc - Naugatuck Reg-Thomaston System | CT1400011 | Clinton | 3,789 | <MRL | <MRL | 0 | No PFAS detected |
| Ctwc - Naugatuck Region-Central System | CT0880011 | Clinton | 22,735 | <MRL | <MRL | 0 | No PFAS detected |
| Ctwc - Shoreline Region-Chester System | CT0261031 | Clinton | 5,030 | <MRL | <MRL | 0 | No PFAS detected |
| Greenwich American Center | CT0570062 | Greenwich | 800 | <MRL | <MRL | 0 | No PFAS detected |
| Groton Utilities | CT0590011 | Groton | 30,200 | <MRL | <MRL | 0 | No PFAS detected |
| Kensington Fire District | CT0070011 | Kensington | 7,553 | <MRL | <MRL | 0 | No PFAS detected |
| Metropolitan District Commission | CT0640011 | Hartford | 390,887 | <MRL | <MRL | 0 | No PFAS detected |
| Middlebury Hamlet | CT0810054 | Prospect | 75 | <MRL | <MRL | 0 | No PFAS detected |
| Middletown Water Department | CT0830011 | Middletown | 41,019 | <MRL | <MRL | 0 | No PFAS detected |
| Mohegan Tribal Utility Authority | 010109005 | Uncasville | 31,961 | <MRL | <MRL | 0 | No PFAS detected |
| New Britain Water Department | CT0890011 | New Britain | 73,534 | <MRL | <MRL | 0 | No PFAS detected |
| New London Dept. Of Public Utilities | CT0950011 | Waterford | 27,620 | <MRL | <MRL | 0 | No PFAS detected |
| South Norwalk Electric & Water | CT1030021 | Wilton | 42,000 | <MRL | <MRL | 0 | No PFAS detected |
| Sterling Engineering Corp. | CT0050062 | Barkhamsted | 110 | <MRL | <MRL | 0 | No PFAS detected |
| Torrington Water Company | CT1430011 | Shelton | 37,915 | <MRL | <MRL | 0 | No PFAS detected |
| Waterbury Water Department | CT1510011 | Waterbury | 107,271 | <MRL | <MRL | 0 | No PFAS detected |
| Waterford Wpca | CT1520071 | Waterford | 16,578 | <MRL | <MRL | 0 | No PFAS detected |
| Watertown Fire District | CT1530011 | Watertown | 6,718 | <MRL | <MRL | 0 | No PFAS detected |
| Watertown Water & Sewer Authority | CT1530021 | Oakville | 9,972 | <MRL | <MRL | 0 | No PFAS detected |
| Winsted Water Works | CT1620011 | Winsted | 7,784 | <MRL | <MRL | 0 | No PFAS detected |
Highest single result for each system; PFOA and PFOS in ppt (ng/L). Entry-point samples, not tap water; screening comparisons, not compliance determinations.