PFAS in Montana Drinking Water
Ranked by number of PFAS compounds detected · Data from EPA SDWIS & UCMR
PFAS in Montana: what the data shows
Montana has 30 cities with PFAS monitoring data from the EPA's UCMR 5 program. PFAS ("forever chemicals") were detected in 21 of those cities (70%), with some cities exceeding the EPA's 2024 maximum contaminant levels of 4 ppt. The state average is better than the national average. 2 cities exceed the EPA MCL for at least one PFAS compound. PFAS are linked to cancer, immune system disruption, and developmental issues. The 2024 EPA rule requires water systems exceeding the MCL to notify customers and reduce levels by 2029. PFAS data comes from the EPA's Unregulated Contaminant Monitoring Rule 5 (UCMR 5), which required large water systems to test for 29 PFAS compounds between 2023–2025. Not all systems have completed testing — cities without data may still have PFAS present.
Cities exceeding EPA MCL (4 ppt each)
PFAS data across Montana
Each dot is a city, colored by overall water quality grade. PFAS-tested cities are shown; those exceeding the 4 ppt EPA MCL appear in red. Size reflects population served.
Top 10 cities by pfas level in Montana
Highest PFAS levels (compounds)
All Montana cities ranked by pfas level
| # | City | Level | Level | Exceeds? | Violations | Grade |
|---|---|---|---|---|---|---|
| 1 | Great Falls | 2 compounds | No | 64 | F | |
| 2 | Kalispell | 2 compounds | Yes | 162 | F | |
| 3 | Billings | 1 compounds | No | 51 | F | |
| 4 | Missoula | 1 compounds | No | 189 | F | |
| 5 | Helena | 1 compounds | No | 90 | F | |
| 6 | Whitefish | 1 compounds | Yes | 42 | F | |
| 7 | Havre | 1 compounds | No | 151 | F | |
| 8 | Miles City | 1 compounds | No | 15 | C+ | |
| 9 | West Yellowstone | 1 compounds | No | 10 | D | |
| 10 | Livingston | 1 compounds | No | 40 | D | |
| 11 | Glendive | 1 compounds | No | 16 | D | |
| 12 | Bigfork | 1 compounds | No | 20 | A- | |
| 13 | Laurel | 1 compounds | No | 6 | C+ | |
| 14 | Hamilton | 1 compounds | No | 20 | D+ | |
| 15 | Big Sky | 1 compounds | No | 17 | F | |
| 16 | Sidney | 1 compounds | No | 27 | F | |
| 17 | Dillon | 1 compounds | No | 36 | F | |
| 18 | Shelby | 1 compounds | No | 50 | D | |
| 19 | Hardin | 1 compounds | No | 6 | F | |
| 20 | Fairfield | 1 compounds | No | 0 | B- | |
| 21 | Pinesdale | 1 compounds | No | 17 | B | |
| 22 | Bozeman | 0 compounds | No | 57 | F | |
| 23 | Butte | 0 compounds | No | 4 | B+ | |
| 24 | Belgrade | 0 compounds | No | 27 | F | |
| 25 | Anaconda | 0 compounds | No | 12 | D+ | |
| 26 | Browning | 0 compounds | No | 40 | F | |
| 27 | Polson | 0 compounds | No | 26 | D+ | |
| 28 | Columbia Falls | 0 compounds | No | 23 | D | |
| 29 | Lewistown | 0 compounds | No | 99 | D | |
| 30 | Libby | 0 compounds | No | 50 | F |
Frequently asked questions about pfas in Montana
Does Montana tap water contain PFAS?
PFAS were detected in 21 of 30 Montana cities tested under EPA's UCMR 5 program. 2 cities exceed the 2024 EPA MCL of 4 ppt for individual PFAS compounds.
How can I remove PFAS from my drinking water in Montana?
Reverse osmosis (RO) systems are the most effective at removing PFAS, typically removing 90%+ of compounds. High-quality activated carbon block filters (NSF 58-certified for RO, or NSF 53 for solid carbon) also provide significant reduction. Standard pitcher filters vary widely in PFAS removal.