PFAS Testing Results
Montana
PFAS testing results for 45 water systems serving 604,648 residents.
2 systems exceed federal PFAS limits, affecting 25,125 residents.
Systems tested
45
11.1% had PFAS detections
Limits exceeded
2
4.4% of systems
Population affected
25K
served by systems over federal limits
Most common compound
11Cl-PF3OUdS
detected in 5 systems
Grade distribution
Every water system gets a letter grade based on how its worst detected PFAS compound compares to the federal Maximum Contaminant Level. Lower grades mean higher contamination.
Communities exceeding federal limits
The water systems in Montana where at least one PFAS compound exceeds the EPA Maximum Contaminant Level, sorted worst first.
| System name | City | Grade | Worst compound | Times over limit | Population |
|---|---|---|---|---|---|
| KALISPELL PUBLIC WORKS | KALISPELL | D | PFOS | 1.6x | 25K |
| ALPINE VILLAGE WUA | COLUMBIA FALLS | D | PFOS | 1.0x | 125 |
Resources for taking action are available in our community toolkit.
What Montana is doing about PFAS
As of April 2026, Montana has not adopted state-level PFAS drinking water standards beyond the federal EPA limits finalized in April 2024. The Montana Department of Environmental Quality has tracked contamination near Malmstrom Air Force Base outside Great Falls, where AFFF firefighting foam releases have affected groundwater.
Public water systems in Montana are subject to the federal compliance timeline requiring initial monitoring by 2027 and treatment installation by 2029.
Based on Montana Department of Environmental Quality publications.
All 45 tested water systems in Montana
Sorted from lowest grade to highest. Click any system name for the full report. Filter by city or name with the search box below.
Showing 45 of 45 systems
| Grade | System name | City | Worst compound | vs. EPA limit | Population |
|---|---|---|---|---|---|
D | KALISPELL PUBLIC WORKS | KALISPELL | PFOS | 1.6× the federal limit | 25K |
D | ALPINE VILLAGE WUA | COLUMBIA FALLS | PFOS | 1.0× the federal limit | 125 |
B | HAMILTON CITY OF | HAMILTON | PFBS | Below detection | 5.6K |
B | MALMSTROM AIR FORCE BASE | MALMSTROM AIR FORCE BASE | PFBA | Below detection | 8.8K |
B | BIG SKY COUNTY WATER AND SEWER DIST 363 | BIG SKY | PFBS | Below detection | 4.1K |
A | ANACONDA WATER DEPARTMENT | ANACONDA | - | Below detection | 6.8K |
A | BELGRADE CITY OF | BELGRADE | - | Below detection | 10K |
A | BILLINGS CITY OF | BILLINGS | - | Below detection | 114K |
A | CO WATER DIST OF BILLINGS HEIGHTS | BILLINGS | - | Below detection | 12K |
A | LOCKWOOD WATER AND SEWER DISTRICT | BILLINGS | - | Below detection | 5.9K |
A | BOZEMAN CITY OF | BOZEMAN | - | Below detection | 56K |
A | BUTTE SILVERBOW WATER DEPT | BUTTE | - | Below detection | 33K |
A | COLUMBIA FALLS CITY OF | COLUMBIA FALLS | - | Below detection | 4.5K |
A | DILLON CITY OF | DILLON | - | Below detection | 4.3K |
A | FAIRFIELD TOWN OF | FAIRFIELD | - | Below detection | 718 |
A | GLENDIVE CITY OF | GLENDIVE | - | Below detection | 4.9K |
A | HARDIN CITY OF | HARDIN | - | Below detection | 3.5K |
A | HELENA WATER SYSTEM | HELENA | - | Below detection | 32K |
A | BIGFORK COUNTY WATER AND SEWER | BIGFORK | - | Below detection | 6.1K |
A | LAUREL MUNICIPAL WATER SYSTEM | LAUREL | - | Below detection | 6.3K |
A | LEWISTOWN CITY OF | LEWISTOWN | - | Below detection | 5.9K |
A | LIBBY CITY OF | LIBBY | - | Below detection | 4.9K |
A | MILES CITY CITY OF | MILES CITY | - | Below detection | 9.6K |
A | MISSOULA WATER | MISSOULA | - | Below detection | 68K |
A | POLSON CITY OF | POLSON | - | Below detection | 5.3K |
A | SHELBY CITY OF | SHELBY | - | Below detection | 4.0K |
A | SIDNEY CITY OF | SIDNEY | - | Below detection | 5.0K |
A | WHITEFISH CITY OF | WHITEFISH | - | Below detection | 10K |
A | BIG PINES TRAILER COURT | MISSOULA | - | Below detection | 78 |
A | SUN PRAIRIE VILLAGE COUNTY | GREAT FALLS | - | Below detection | 1.8K |
A | HAVRE CITY OF | HAVRE | - | Below detection | 9.9K |
A | GREAT FALLS CITY OF | GREAT FALLS | - | Below detection | 60K |
A | LIVINGSTON CITY OF | LIVINGSTON | - | Below detection | 7.5K |
A | FRENCHTOWN HIGH SCHOOL | FRENCHTOWN | - | Below detection | 550 |
A | FLATHEAD COUNTY WATER AND SEWER | KALISPELL | - | Below detection | 7.8K |
A | CULLIGAN WATER CONDITIONING GREAT FALLS | GREAT FALLS | - | Below detection | 900 |
A | PINESDALE TOWN OF | PINESDALE | - | Below detection | 800 |
A | WEST YELLOWSTONE TOWN OF | WEST YELLOWSTONE | - | Below detection | 9.9K |
A | RIVER ROCK COUNTY WATER AND SEWER DIST | BELGRADE | - | Below detection | 4.2K |
A | UNIVERSITY OF MONTANA | MISSOULA | - | Below detection | 15K |
A | PHANTOM HILLS WATER SYSTEM | MISSOULA | - | Below detection | 810 |
A | MONTANA STATE UNIVERSITY BILLINGS | BILLINGS | - | Below detection | 3.0K |
A | MONTANA STATE UNIVERSITY BOZEMAN | BOZEMAN | - | Below detection | 19K |
A | ROCKY MOUNTAIN COLLEGE | BILLINGS | - | Below detection | 5.7K |
A | BLACK ROCK ESTATES SUBDIVISION | BILLINGS | - | Below detection | 75 |
Check your water system
Enter your zip code to see the PFAS results for the water system that serves your home.
Where this data comes from
- EPA Unregulated Contaminant Monitoring Rule, 5th cycle (UCMR 5)
- Testing period: 2023 to 2026
- Federal limits: EPA Maximum Contaminant Levels finalized April 2024
- Read the full methodology