Montana tap water
0 of 38 Montana water systems with full PFAS testing (0%) averaged above a 2024 federal PFAS level at one or more sampling points.
- 804 active community water systems in the EPA file; 31 serve 3,300+ people and have a full PFAS set.
- 80 systems had at least one health-based violation since 2021-10-26.
- 4 systems report a lead 90th percentile above 15 ppb (some results are old; check each system page).
Largest systems
| System | People served | PFAS above a 2024 level? | Health-based violations since 2021-10-26 |
|---|---|---|---|
| Billings City of | 114,000 | No | 0 |
| Missoula Water | 68,200 | No | 0 |
| Great Falls City of | 60,000 | No | 0 |
| Bozeman City of | 56,000 | No | 0 |
| Butte Silverbow Water dept | 33,000 | No | 0 |
| Helena Water System | 32,091 | No | 3 |
| Kalispell Public Works | 25,000 | No | 0 |
| Belgrade City of | 10,460 | No | 0 |
All 4 utilities with a page in Montana
- Billings City of 114,000
- Bozeman City of 56,000
- Great Falls City of 60,000
- Missoula Water 68,200
Why not "the state's water quality"? You drink from one utility, not a state. Rollups count systems, not people, so one large utility counts the same as a small one. Use the system pages for your actual water.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.