Montana — 1st District
119th Congress · 138 ZIP codes · Avg score 56/100 · Grade C · Updated 2026-07-19
Data: EPA SDWIS / Census 119th Congress Last verified: 2026-07-19
ZipCheckup tracks water safety for 138 ZIP codes in Montana's 1st District: the district earns a grade C (56/100). 319 EPA violations on record, 26 health-based.
Top Contaminants
ZIP Codes in This District
100 ZIP codes tracked in Montana's 1st District. Showing top 50 by safety score.
| # | ZIP Code | City | Safety Score | Grade | Violations |
|---|---|---|---|---|---|
| 1 | 59716 | Big Sky | 70 | B | 1 |
| 2 | 59729 | Ennis | 70 | B | 1 |
| 3 | 59730 | Gallatin Gateway | 70 | B | 1 |
| 4 | 59752 | Three Forks | 70 | B | 1 |
| 5 | 59754 | Twin Bridges | 70 | B | 0 |
| 6 | 59823 | Bonner | 70 | B | 0 |
| 7 | 59828 | Corvallis | 70 | B | 0 |
| 8 | 59840 | Hamilton | 70 | B | 1 |
| 9 | 59846 | Huson | 70 | B | 1 |
| 10 | 59872 | Superior | 70 | B | 0 |
| 11 | 59925 | Marion | 70 | B | 0 |
| 12 | 59935 | Troy | 70 | B | 0 |
| 13 | 59801 | Missoula | 69 | C | 3 |
| 14 | 59806 | Missoula | 69 | C | 3 |
| 15 | 59820 | Alberton | 69 | C | 4 (1 health) |
| 16 | 59860 | Polson | 69 | C | 2 |
| 17 | 59833 | Florence | 68 | C | 1 |
| 18 | 59859 | Plains | 68 | C | 1 |
| 19 | 59758 | West Yellowstone | 67 | C | 4 |
| 20 | 59771 | Bozeman | 67 | C | 3 |
| 21 | 59917 | Eureka | 67 | C | 6 |
| 22 | 59739 | Lima | 66 | C | 0 |
| 23 | 59749 | Sheridan | 66 | C | 1 |
| 24 | 59829 | Darby | 66 | C | 9 (1 health) |
| 25 | 59834 | Frenchtown | 66 | C | 1 |
| 26 | 59841 | Pinesdale | 66 | C | 0 |
| 27 | 59844 | Heron | 66 | C | 1 |
| 28 | 59853 | Noxon | 66 | C | 0 |
| 29 | 59870 | Stevensville | 66 | C | 8 |
| 30 | 59922 | Lakeside | 66 | C | 0 |
| 31 | 59930 | Rexford | 66 | C | 0 |
| 32 | 59725 | Dillon | 65 | C | 11 |
| 33 | 59741 | Manhattan | 65 | C | 10 |
| 34 | 59807 | Missoula | 65 | C | 3 |
| 35 | 59812 | Missoula | 65 | C | 3 |
| 36 | 59842 | Haugan | 65 | C | 2 |
| 37 | 59864 | Ronan | 65 | C | 10 |
| 38 | 59868 | Seeley Lake | 65 | C | 0 |
| 39 | 59918 | Fortine | 65 | C | 2 |
| 40 | 59931 | Rollins | 65 | C | 2 |
| 41 | 59937 | Whitefish | 65 | C | 1 |
| 42 | 59427 | Cut Bank | 64 | C | 2 |
| 43 | 59802 | Missoula | 64 | C | 3 |
| 44 | 59803 | Missoula | 64 | C | 3 |
| 45 | 59808 | Missoula | 64 | C | 3 |
| 46 | 59847 | Lolo | 64 | C | 3 |
| 47 | 59855 | Pablo | 64 | C | 5 (2 health) |
| 48 | 59873 | Thompson Falls | 64 | C | 4 |
| 49 | 59919 | Hungry Horse | 64 | C | 4 |
| 50 | 59486 | Valier | 63 | C | 6 |
Overview
Montana's 1st District encompasses 138 ZIP codes tracked by ZipCheckup. The district's average Home Safety Score is C (56/100).
319 EPA violations have been recorded across this district's water systems. 26 are health-based violations. About 51% of tracked ZIP codes have at least one violation.
Top Contaminants
The most frequently cited water quality issues in this district:
- Surface Water Treatment Rule - 93 violations
- Stage 1 DBP Rule - 63 violations
- Consumer Confidence Report Rule - 54 violations
- Total Trihalomethanes (TTHM) - 35 violations
- Arsenic - 18 violations
Housing Context
Homes in this district were built on average around 1982 (~44 years old). Older homes may have lead pipes or solder - consider a water filter if your home predates 1986.
Data Sources
- Water quality violations: EPA Safe Drinking Water Information System (SDWIS)
- Congressional district boundaries: U.S. Census Bureau, 119th Congress
- Housing age: U.S. Census Bureau American Community Survey
Updated daily. Data covers 138 ZIP codes in Montana's 1st District.