Out of 86 ZIP codes with data in Idaho, these are the highest-ranked areas for recorded epa violations. See also: National ZIP Codes with Most EPA Water Violations | All Idaho Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 86 |
| Highest value | 149 |
| Median value | 12 |
| State | Idaho |
Top 86 Worst ZIP Codes
| Rank | ZIP Code | City | State | Recorded EPA Violations | Safety Score |
|---|---|---|---|---|---|
| 1 | 83623 | Glenns Ferry | ID | 149 | — |
| 2 | 83647 | Mountain Home | ID | 149 | — |
| 3 | 83440 | Rexburg | ID | 138 | — |
| 4 | 83714 | Garden City | ID | 127 | 62/100 |
| 5 | 83704 | Boise | ID | 125 | 63/100 |
| 6 | 83706 | Boise | ID | 125 | 80/100 |
| 7 | 83648 | Mountain Home A F B | ID | 111 | 67/100 |
| 8 | 83221 | Blackfoot | ID | 93 | — |
| 9 | 83236 | Firth | ID | 91 | — |
| 10 | 83638 | Mccall | ID | 73 | 50/100 |
| 11 | 83401 | Idaho Falls | ID | 65 | 71/100 |
| 12 | 83338 | Jerome | ID | 63 | — |
| 13 | 83406 | Idaho Falls | ID | 62 | 72/100 |
| 14 | 83421 | Chester | ID | 59 | — |
| 15 | 83445 | Saint Anthony | ID | 59 | — |
| 16 | 83460 | Rexburg | ID | 58 | — |
| 17 | 83442 | Rigby | ID | 57 | — |
| 18 | 83427 | Iona | ID | 55 | — |
| 19 | 83501 | Lewiston | ID | 54 | 92/100 |
| 20 | 83422 | Driggs | ID | 47 | — |
| 21 | 83452 | Tetonia | ID | 45 | — |
| 22 | 83832 | Genesee | ID | 42 | — |
| 23 | 83619 | Fruitland | ID | 36 | — |
| 24 | 83661 | Payette | ID | 35 | — |
| 25 | 83655 | New Plymouth | ID | 34 | — |
| 26 | 83858 | Rathdrum | ID | 32 | 50/100 |
| 27 | 83686 | Nampa | ID | 30 | 68/100 |
| 28 | 83340 | Ketchum | ID | 28 | 58/100 |
| 29 | 83353 | Sun Valley | ID | 28 | 58/100 |
| 30 | 83333 | Hailey | ID | 26 | 58/100 |
| 31 | 83843 | Moscow | ID | 25 | 57/100 |
| 32 | 83801 | Athol | ID | 24 | — |
| 33 | 83844 | Moscow | ID | 24 | 59/100 |
| 34 | 83814 | Coeur D Alene | ID | 23 | 52/100 |
| 35 | 83872 | Viola | ID | 23 | — |
| 36 | 83202 | Pocatello | ID | 22 | 67/100 |
| 37 | 83316 | Buhl | ID | 22 | 75/100 |
| 38 | 83448 | Sugar City | ID | 21 | — |
| 39 | 83451 | Teton | ID | 21 | — |
| 40 | 83607 | Caldwell | ID | 21 | 77/100 |
| 41 | 83301 | Twin Falls | ID | 19 | 76/100 |
| 42 | 83328 | Filer | ID | 16 | — |
| 43 | 83318 | Burley | ID | 15 | — |
| 44 | 83536 | Kamiah | ID | 12 | — |
| 45 | 83543 | Nezperce | ID | 12 | — |
| 46 | 83709 | Boise | ID | 12 | 78/100 |
| 47 | 83854 | Post Falls | ID | 12 | 61/100 |
| 48 | 83211 | American Falls | ID | 11 | — |
| 49 | 83263 | Preston | ID | 11 | 79/100 |
| 50 | 83864 | Sandpoint | ID | 11 | 63/100 |
| 51 | 83651 | Nampa | ID | 9 | 80/100 |
| 52 | 83687 | Nampa | ID | 9 | 80/100 |
| 53 | 83404 | Idaho Falls | ID | 7 | 81/100 |
| 54 | 83713 | Boise | ID | 6 | 80/100 |
| 55 | 83836 | Hope | ID | 6 | — |
| 56 | 83869 | Spirit Lake | ID | 6 | — |
| 57 | 83237 | Franklin | ID | 5 | — |
| 58 | 83274 | Shelley | ID | 5 | — |
| 59 | 83336 | Heyburn | ID | 5 | — |
| 60 | 83835 | Hayden | ID | 5 | 64/100 |
| 61 | 83350 | Rupert | ID | 4 | — |
| 62 | 83201 | Pocatello | ID | 3 | 82/100 |
| 63 | 83204 | Pocatello | ID | 3 | 82/100 |
| 64 | 83209 | Pocatello | ID | 3 | 82/100 |
| 65 | 83341 | Kimberly | ID | 3 | — |
| 66 | 83616 | Eagle | ID | 3 | 83/100 |
| 67 | 83825 | Dover | ID | 3 | — |
| 68 | 83841 | Laclede | ID | 3 | — |
| 69 | 83330 | Gooding | ID | 2 | — |
| 70 | 83628 | Homedale | ID | 2 | — |
| 71 | 83634 | Kuna | ID | 2 | 83/100 |
| 72 | 83702 | Boise | ID | 2 | 82/100 |
| 73 | 83703 | Boise | ID | 2 | 83/100 |
| 74 | 83822 | Oldtown | ID | 2 | — |
| 75 | 83856 | Priest River | ID | 2 | — |
| 76 | 83402 | Idaho Falls | ID | 1 | 83/100 |
| 77 | 83605 | Caldwell | ID | 1 | 83/100 |
| 78 | 83626 | Greenleaf | ID | 1 | — |
| 79 | 83639 | Marsing | ID | 1 | — |
| 80 | 83642 | Meridian | ID | 1 | 67/100 |
| 81 | 83660 | Parma | ID | 1 | — |
| 82 | 83669 | Star | ID | 1 | 83/100 |
| 83 | 83804 | Blanchard | ID | 1 | — |
| 84 | 83815 | Coeur D Alene | ID | 1 | 67/100 |
| 85 | 83840 | Kootenai | ID | 1 | 66/100 |
| 86 | 83852 | Ponderay | ID | 1 | 66/100 |
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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