All 34 systems had complete monitoring. 0 reached at least one study comparison level; 34 did not. “Study comparison level” means the dated EPA technical cutoff used in this January 2026 research release. It does not determine household exposure, health risk, or current legal compliance.
Find your water system
ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
System counts in Montana
Each count shows how many included water systems reached the named study level.
| Study comparison | Systems reaching level | Water systems included | Percent |
|---|---|---|---|
| PFOA: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 0 | 34 | 0.0% |
| PFOS: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 0 | 34 | 0.0% |
| PFHxS: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 34 | 0.0% |
| PFNA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 34 | 0.0% |
| HFPO-DA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 34 | 0.0% |
| Hazard Index: study level 1.5 with at least two detected components (April 2024 EPA level: 1) | 0 | 34 | 0.0% |
Community water systems with complete monitoring
Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study comparison |
|---|---|---|---|---|---|
| ALPINE VILLAGE WUA | MT0003229 | 125 | Ground water | 1 | Below the study levels |
| ANACONDA WATER DEPARTMENT | MT0000016 | 6,750 | Ground water | 1 | Below the study levels |
| BELGRADE CITY OF | MT0000136 | 10,460 | Ground water | 7 | Below the study levels |
| BIG PINES TRAILER COURT | MT0000450 | 78 | Ground water | 1 | Below the study levels |
| BIG SKY COUNTY WATER AND SEWER DIST 363 | MT0002385 | 4,132 | Ground water | 2 | Below the study levels |
| BILLINGS CITY OF | MT0000153 | 114,000 | Surface water | 1 | Below the study levels |
| BLACK ROCK ESTATES SUBDIVISION | MT0004881 | 75 | Ground water | 1 | Below the study levels |
| BOZEMAN CITY OF | MT0000161 | 56,000 | Surface water | 2 | Below the study levels |
| BUTTE SILVERBOW WATER DEPT | MT0000170 | 33,000 | Surface water | 3 | Below the study levels |
| COLUMBIA FALLS CITY OF | MT0000181 | 4,450 | Ground water | 1 | Below the study levels |
| DILLON CITY OF | MT0000201 | 4,300 | Ground water | 3 | Below the study levels |
| FAIRFIELD TOWN OF | MT0000212 | 718 | Ground water | 5 | Below the study levels |
| FLATHEAD COUNTY WATER AND SEWER | MT0001744 | 7,775 | Ground water | 4 | Below the study levels |
| GREAT FALLS CITY OF | MT0000525 | 60,000 | Surface water | 1 | Below the study levels |
| HAMILTON CITY OF | MT0000234 | 5,660 | Ground water | 4 | Below the study levels |
| HARDIN CITY OF | MT0000235 | 3,500 | Surface water | 1 | Below the study levels |
| HAVRE CITY OF | MT0000524 | 9,921 | Surface water | 1 | Below the study levels |
| HELENA WATER SYSTEM | MT0000241 | 32,091 | Surface water | 3 | Below the study levels |
| KALISPELL PUBLIC WORKS | MT0000259 | 25,000 | Ground water | 8 | Below the study levels |
| LAUREL MUNICIPAL WATER SYSTEM | MT0000270 | 6,339 | Surface water | 1 | Below the study levels |
| LEWISTOWN CITY OF | MT0000271 | 5,923 | Ground water | 1 | Below the study levels |
| LIVINGSTON CITY OF | MT0000573 | 7,500 | Ground water | 6 | Below the study levels |
| LOCKWOOD WATER AND SEWER DISTRICT | MT0000156 | 5,900 | Surface water | 1 | Below the study levels |
| MALMSTROM AIR FORCE BASE | MT0000515 | 8,850 | Surface water purchased | 2 | Below the study levels |
| MILES CITY CITY OF | MT0000291 | 9,565 | Surface water | 1 | Below the study levels |
| MISSOULA WATER | MT0000294 | 68,200 | Ground water | 23 | Below the study levels |
| PHANTOM HILLS WATER SYSTEM | MT0004379 | 810 | Ground water | 1 | Below the study levels |
| PINESDALE TOWN OF | MT0002926 | 800 | Surface water | 3 | Below the study levels |
| RIVER ROCK COUNTY WATER AND SEWER DIST | MT0004082 | 4,200 | Ground water | 1 | Below the study levels |
| SHELBY CITY OF | MT0000328 | 3,970 | Ground water | 1 | Below the study levels |
| SUN PRAIRIE VILLAGE COUNTY | MT0000521 | 1,800 | Ground water | 1 | Below the study levels |
| TOWN OF BROWNING | 083090091 | 4,671 | Surface water purchased | 1 | Below the study levels |
| WEST YELLOWSTONE TOWN OF | MT0003136 | 9,899 | Ground water | 3 | Below the study levels |
| WHITEFISH CITY OF | MT0000357 | 10,418 | Surface water | 1 | Below the study levels |
What is included
Each active community water system with complete monitoring is counted once, even if it is linked with several ZIP codes. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Montana's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.