All 39 systems met the sampling requirement for a yearly average. Of those systems, 0 had at least one yearly average above an EPA comparison level and 39 did not.
EPA-based study benchmark: a fixed, unrounded research cutoff used to reproduce EPA’s final UCMR 5 technical-assistance classification based on the April 2024 federal levels. It is not a current federal or state standard. The label does not determine compliance, household exposure, or health risk.
State rules: The labels on this page use fixed research cutoffs based on the April 2024 federal levels. Montana may use different current standards or guidance. These UCMR 5 results do not determine current federal or state compliance. Find the official Montana drinking-water program →
Find your water system
A ZIP code finds possible public water systems for an area; it cannot identify the supplier for a specific home. Confirm the provider using a water bill or utility record.
System counts in Montana
Each count shows how many included water systems had a yearly average above the named EPA comparison level.
| EPA rounding cutoff | Systems above comparison level | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4 ppt level; unrounded average ≥4.05 ppt after applying EPA rounding | 0 | 39 | 0.0% |
| PFOS: 4 ppt level; unrounded average ≥4.05 ppt after applying EPA rounding | 0 | 39 | 0.0% |
| PFHxS: 10 ppt level; unrounded average ≥15 ppt after applying EPA rounding | 0 | 39 | 0.0% |
| PFNA: 10 ppt level; unrounded average ≥15 ppt after applying EPA rounding | 0 | 39 | 0.0% |
| HFPO-DA: 10 ppt level; unrounded average ≥15 ppt after applying EPA rounding | 0 | 39 | 0.0% |
| Hazard Index: 1 level; unrounded index ≥1.5 and at least two detected components | 0 | 39 | 0.0% |
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had every required sample needed to calculate a yearly average. It does not mean every location or home was tested. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | EPA comparison result |
|---|---|---|---|---|---|
| ALPINE VILLAGE WUA | MT0003229 | 125 | Ground water | 1 | No available average above comparison levels |
| ANACONDA WATER DEPARTMENT | MT0000016 | 6,750 | Ground water | 1 | No available average above comparison levels |
| BELGRADE CITY OF | MT0000136 | 10,460 | Ground water | 7 | No available average above comparison levels |
| BIG PINES TRAILER COURT | MT0000450 | 78 | Ground water | 1 | No available average above comparison levels |
| BIG SKY COUNTY WATER AND SEWER DIST 363 | MT0002385 | 4,132 | Ground water | 2 | No available average above comparison levels |
| BIGFORK COUNTY WATER AND SEWER | MT0000262 | 6,100 | Ground water | 2 | No available average above comparison levels |
| BILLINGS CITY OF | MT0000153 | 114,000 | Surface water | 1 | No available average above comparison levels |
| BLACK ROCK ESTATES SUBDIVISION | MT0004881 | 75 | Ground water | 1 | No available average above comparison levels |
| BOZEMAN CITY OF | MT0000161 | 56,000 | Surface water | 2 | No available average above comparison levels |
| BUTTE SILVERBOW WATER DEPT | MT0000170 | 33,000 | Surface water | 3 | No available average above comparison levels |
| COLUMBIA FALLS CITY OF | MT0000181 | 4,450 | Ground water | 1 | No available average above comparison levels |
| DILLON CITY OF | MT0000201 | 4,300 | Ground water | 3 | No available average above comparison levels |
| FAIRFIELD TOWN OF | MT0000212 | 718 | Ground water | 5 | No available average above comparison levels |
| FLATHEAD COUNTY WATER AND SEWER | MT0001744 | 7,775 | Ground water | 4 | No available average above comparison levels |
| GLENDIVE CITY OF | MT0000229 | 4,873 | Surface water | 1 | No available average above comparison levels |
| GREAT FALLS CITY OF | MT0000525 | 60,000 | Surface water | 1 | No available average above comparison levels |
| HAMILTON CITY OF | MT0000234 | 5,660 | Ground water | 4 | No available average above comparison levels |
| HARDIN CITY OF | MT0000235 | 3,500 | Surface water | 1 | No available average above comparison levels |
| HAVRE CITY OF | MT0000524 | 9,921 | Surface water | 1 | No available average above comparison levels |
| HELENA WATER SYSTEM | MT0000241 | 32,091 | Surface water | 3 | No available average above comparison levels |
| KALISPELL PUBLIC WORKS | MT0000259 | 25,000 | Ground water | 8 | No available average above comparison levels |
| LAUREL MUNICIPAL WATER SYSTEM | MT0000270 | 6,339 | Surface water | 1 | No available average above comparison levels |
| LEWISTOWN CITY OF | MT0000271 | 5,923 | Ground water | 1 | No available average above comparison levels |
| LIBBY CITY OF | MT0000274 | 4,892 | Surface water | 1 | No available average above comparison levels |
| LIVINGSTON CITY OF | MT0000573 | 7,500 | Ground water | 6 | No available average above comparison levels |
| LOCKWOOD WATER AND SEWER DISTRICT | MT0000156 | 5,900 | Surface water | 1 | No available average above comparison levels |
| MALMSTROM AIR FORCE BASE | MT0000515 | 8,850 | Surface water purchased | 2 | No available average above comparison levels |
| MILES CITY CITY OF | MT0000291 | 9,565 | Surface water | 1 | No available average above comparison levels |
| MISSOULA WATER | MT0000294 | 68,200 | Ground water | 23 | No available average above comparison levels |
| PHANTOM HILLS WATER SYSTEM | MT0004379 | 810 | Ground water | 1 | No available average above comparison levels |
| PINESDALE TOWN OF | MT0002926 | 800 | Surface water | 3 | No available average above comparison levels |
| POLSON CITY OF | MT0000308 | 5,300 | Ground water | 5 | No available average above comparison levels |
| RIVER ROCK COUNTY WATER AND SEWER DIST | MT0004082 | 4,200 | Ground water | 1 | No available average above comparison levels |
| SHELBY CITY OF | MT0000328 | 3,970 | Ground water | 1 | No available average above comparison levels |
| SIDNEY CITY OF | MT0000330 | 5,000 | Ground water | 2 | No available average above comparison levels |
| SUN PRAIRIE VILLAGE COUNTY | MT0000521 | 1,800 | Ground water | 1 | No available average above comparison levels |
| TOWN OF BROWNING | 083090091 | 4,671 | Surface water purchased | 1 | No available average above comparison levels |
| WEST YELLOWSTONE TOWN OF | MT0003136 | 9,899 | Ground water | 3 | No available average above comparison levels |
| WHITEFISH CITY OF | MT0000357 | 10,418 | Surface water | 1 | No available average above comparison levels |
What is included
Each active community water system with enough required samples for a yearly average 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.