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.
46 of the 1,172 public water systems listed for Montana 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 1,172 Montana systems, including those not tested · Download all Montana results (CSV, gzip)
| System | PWSID | City | Population | PFOA (ppt) | PFOS (ppt) | HI | Highest single result |
|---|---|---|---|---|---|---|---|
| Kalispell Public Works | MT0000259 | Kalispell | 25,000 | <MRL | 6.6 | 0.5 | PFOS 1–3 × its limit |
| Alpine Village Wua | MT0003229 | Columbia Falls | 125 | <MRL | 4.1 | 0 | PFOS 1–3 × its limit |
| Big Sky County Water And Sewer Dist 363 | MT0002385 | Big Sky | 4,132 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Hamilton City Of | MT0000234 | Hamilton | 5,660 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Malmstrom Air Force Base | MT0000515 | Malmstrom Air Force Base | 8,850 | <MRL | <MRL | 0 | Other PFAS detected |
| Anaconda Water Department | MT0000016 | Anaconda | 6,750 | <MRL | <MRL | 0 | No PFAS detected |
| Belgrade City Of | MT0000136 | Belgrade | 10,460 | <MRL | <MRL | 0 | No PFAS detected |
| Big Pines Trailer Court | MT0000450 | Missoula | 78 | <MRL | <MRL | 0 | No PFAS detected |
| Bigfork County Water And Sewer | MT0000262 | Bigfork | 6,100 | <MRL | <MRL | 0 | No PFAS detected |
| Billings City Of | MT0000153 | Billings | 114,000 | <MRL | <MRL | 0 | No PFAS detected |
| Billings Heights Co Water Dist Of | MT0000155 | Billings | 12,000 | <MRL | <MRL | 0 | No PFAS detected |
| Black Rock Estates Subdivision | MT0004881 | Billings | 75 | <MRL | <MRL | 0 | No PFAS detected |
| Bozeman City Of | MT0000161 | Bozeman | 56,000 | <MRL | <MRL | 0 | No PFAS detected |
| Butte Silverbow Water Dept | MT0000170 | Butte | 33,000 | <MRL | <MRL | 0 | No PFAS detected |
| Columbia Falls City Of | MT0000181 | Columbia Falls | 4,450 | <MRL | <MRL | 0 | No PFAS detected |
| Culligan Water Conditioning Great Falls | MT0002630 | Great Falls | 900 | <MRL | <MRL | 0 | No PFAS detected |
| Dillon City Of | MT0000201 | Dillon | 4,300 | <MRL | <MRL | 0 | No PFAS detected |
| Fairfield Town Of | MT0000212 | Fairfield | 718 | <MRL | <MRL | 0 | No PFAS detected |
| Flathead County Water And Sewer | MT0001744 | Kalispell | 9,520 | <MRL | <MRL | 0 | No PFAS detected |
| Frenchtown High School | MT0000856 | Frenchtown | 550 | <MRL | <MRL | 0 | No PFAS detected |
| Glendive City Of | MT0000229 | Glendive | 4,873 | <MRL | <MRL | 0 | No PFAS detected |
| Great Falls City Of | MT0000525 | Great Falls | 60,000 | <MRL | <MRL | 0 | No PFAS detected |
| Hardin City Of | MT0000235 | Hardin | 3,500 | <MRL | <MRL | 0 | No PFAS detected |
| Havre City Of | MT0000524 | Havre | 9,921 | <MRL | <MRL | 0 | No PFAS detected |
| Helena Water System | MT0000241 | Helena | 32,091 | <MRL | <MRL | 0 | No PFAS detected |
| Laurel Municipal Water System | MT0000270 | Laurel | 6,339 | <MRL | <MRL | 0 | No PFAS detected |
| Lewistown City Of | MT0000271 | Lewistown | 5,923 | <MRL | <MRL | 0 | No PFAS detected |
| Libby City Of | MT0000274 | Libby | 4,892 | <MRL | <MRL | 0 | No PFAS detected |
| Livingston City Of | MT0000573 | Livingston | 9,200 | <MRL | <MRL | 0 | No PFAS detected |
| Lockwood Water And Sewer District | MT0000156 | Billings | 5,900 | <MRL | <MRL | 0 | No PFAS detected |
| Miles City City Of | MT0000291 | Miles City | 9,565 | <MRL | <MRL | 0 | No PFAS detected |
| Missoula Water | MT0000294 | Missoula | 68,200 | <MRL | <MRL | 0 | No PFAS detected |
| Montana State University Billings | MT0004788 | Billings | 2,999 | <MRL | <MRL | 0 | No PFAS detected |
| Montana State University Bozeman | MT0004790 | Bozeman | 19,200 | <MRL | <MRL | 0 | No PFAS detected |
| Phantom Hills Water System | MT0004379 | Missoula | 810 | <MRL | <MRL | 0 | No PFAS detected |
| Pinesdale Town Of | MT0002926 | Pinesdale | 800 | <MRL | <MRL | 0 | No PFAS detected |
| Polson City Of | MT0000308 | Polson | 5,300 | <MRL | <MRL | 0 | No PFAS detected |
| River Rock County Water And Sewer Dist | MT0004082 | Belgrade | 4,200 | <MRL | <MRL | 0 | No PFAS detected |
| Rocky Mountain College | MT0004796 | Billings | 5,700 | <MRL | <MRL | 0 | No PFAS detected |
| Shelby City Of | MT0000328 | Shelby | 3,970 | <MRL | <MRL | 0 | No PFAS detected |
| Sidney City Of | MT0000330 | Sidney | 5,000 | <MRL | <MRL | 0 | No PFAS detected |
| Sun Prairie Village County | MT0000521 | Great Falls | 1,800 | <MRL | <MRL | 0 | No PFAS detected |
| Town Of Browning | 083090091 | Browning | 4,671 | <MRL | <MRL | 0 | No PFAS detected |
| University Of Montana | MT0004204 | Missoula | 15,000 | <MRL | <MRL | 0 | No PFAS detected |
| West Yellowstone Town Of | MT0003136 | West Yellowstone | 9,899 | <MRL | <MRL | 0 | No PFAS detected |
| Whitefish City Of | MT0000357 | Whitefish | 10,418 | <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.