Out of 54 ZIP codes with data in Montana, these are the highest-ranked areas for recorded epa violations. See also: National ZIP Codes with Most EPA Water Violations | All Montana Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 54 |
| Highest value | 133 |
| Median value | 4 |
| State | Montana |
Top 54 Worst ZIP Codes
| Rank | ZIP Code | City | State | Recorded EPA Violations | Safety Score |
|---|---|---|---|---|---|
| 1 | 59602 | Helena | MT | 133 | 50/100 |
| 2 | 59404 | Great Falls | MT | 82 | — |
| 3 | 59019 | Columbus | MT | 80 | — |
| 4 | 59069 | Reed Point | MT | 80 | — |
| 5 | 59601 | Helena | MT | 41 | 51/100 |
| 6 | 59101 | Billings | MT | 38 | 72/100 |
| 7 | 59901 | Kalispell | MT | 38 | 35/100 |
| 8 | 59106 | Billings | MT | 34 | 73/100 |
| 9 | 59442 | Fort Benton | MT | 32 | — |
| 10 | 59416 | Brady | MT | 28 | — |
| 11 | 59425 | Conrad | MT | 28 | — |
| 12 | 59923 | Libby | MT | 25 | 57/100 |
| 13 | 59912 | Columbia Falls | MT | 23 | 59/100 |
| 14 | 59808 | Missoula | MT | 21 | 60/100 |
| 15 | 59714 | Belgrade | MT | 10 | 63/100 |
| 16 | 59864 | Ronan | MT | 10 | — |
| 17 | 59501 | Havre | MT | 9 | 65/100 |
| 18 | 59860 | Polson | MT | 9 | 63/100 |
| 19 | 59105 | Billings | MT | 8 | 80/100 |
| 20 | 59323 | Colstrip | MT | 8 | — |
| 21 | 59414 | Black Eagle | MT | 7 | — |
| 22 | 59635 | East Helena | MT | 7 | — |
| 23 | 59301 | Miles City | MT | 6 | 65/100 |
| 24 | 59932 | Somers | MT | 6 | — |
| 25 | 59405 | Great Falls | MT | 5 | — |
| 26 | 59102 | Billings | MT | 4 | 83/100 |
| 27 | 59711 | Anaconda | MT | 4 | — |
| 28 | 59804 | Missoula | MT | 4 | — |
| 29 | 59044 | Laurel | MT | 3 | 82/100 |
| 30 | 59440 | Floweree | MT | 3 | — |
| 31 | 59468 | Power | MT | 3 | — |
| 32 | 59625 | Helena | MT | 3 | — |
| 33 | 59701 | Butte | MT | 3 | 66/100 |
| 34 | 59715 | Bozeman | MT | 3 | 66/100 |
| 35 | 59727 | Divide | MT | 3 | 66/100 |
| 36 | 59748 | Ramsay | MT | 3 | — |
| 37 | 59750 | Butte | MT | 3 | — |
| 38 | 59824 | Charlo | MT | 3 | — |
| 39 | 59068 | Red Lodge | MT | 2 | — |
| 40 | 59230 | Glasgow | MT | 2 | — |
| 41 | 59330 | Glendive | MT | 2 | 66/100 |
| 42 | 59644 | Townsend | MT | 2 | — |
| 43 | 59802 | Missoula | MT | 2 | 66/100 |
| 44 | 59803 | Missoula | MT | 2 | 66/100 |
| 45 | 59833 | Florence | MT | 2 | — |
| 46 | 59847 | Lolo | MT | 2 | — |
| 47 | 59072 | Roundup | MT | 1 | — |
| 48 | 59457 | Lewistown | MT | 1 | 66/100 |
| 49 | 59634 | Clancy | MT | 1 | — |
| 50 | 59716 | Big Sky | MT | 1 | 66/100 |
| 51 | 59718 | Bozeman | MT | 1 | 66/100 |
| 52 | 59730 | Gallatin Gateway | MT | 1 | — |
| 53 | 59801 | Missoula | MT | 1 | 65/100 |
| 54 | 59937 | Whitefish | MT | 1 | 50/100 |
Methodology
Violation counts include all types recorded in the EPA SDWIS database: Maximum Contaminant Level (MCL) violations, treatment technique violations, and monitoring/reporting violations. Both resolved and unresolved violations are counted. Higher counts may reflect longer system histories or larger service areas.
Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-08-31.
Frequently Asked Questions
What counts as an EPA water violation?
EPA violations include exceeding Maximum Contaminant Levels (MCLs), failing to treat water properly (treatment technique violations), and not testing or reporting on schedule (monitoring violations). Health-based violations are the most serious.
Does a high violation count mean the water is unsafe now?
Not necessarily. Many violations are historical or monitoring-related. However, a pattern of repeated violations indicates systemic issues with water system management or infrastructure.
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