Out of 145 ZIP codes with data in Idaho, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes with Highest Radon Risk | All Idaho Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 145 |
| Lowest value | Zone 1 (High) |
| Median value | Zone 1 (High) |
| State | Idaho |
100 Lowest-Ranked ZIP Codes
| Rank | ZIP Code | City | State | Radon Zone | Safety Score |
|---|---|---|---|---|---|
| 1 | 83638 | Mccall | ID | Zone 1 (High) | 50/100 |
| 2 | 83858 | Rathdrum | ID | Zone 1 (High) | 50/100 |
| 3 | 83814 | Coeur D Alene | ID | Zone 1 (High) | 52/100 |
| 4 | 83843 | Moscow | ID | Zone 1 (High) | 57/100 |
| 5 | 83333 | Hailey | ID | Zone 1 (High) | 58/100 |
| 6 | 83340 | Ketchum | ID | Zone 1 (High) | 58/100 |
| 7 | 83353 | Sun Valley | ID | Zone 1 (High) | 58/100 |
| 8 | 83844 | Moscow | ID | Zone 1 (High) | 59/100 |
| 9 | 83854 | Post Falls | ID | Zone 1 (High) | 61/100 |
| 10 | 83864 | Sandpoint | ID | Zone 1 (High) | 63/100 |
| 11 | 83835 | Hayden | ID | Zone 1 (High) | 64/100 |
| 12 | 83840 | Kootenai | ID | Zone 1 (High) | 66/100 |
| 13 | 83852 | Ponderay | ID | Zone 1 (High) | 66/100 |
| 14 | 83815 | Coeur D Alene | ID | Zone 1 (High) | 67/100 |
| 15 | 83837 | Kellogg | ID | Zone 1 (High) | 67/100 |
| 16 | 83868 | Smelterville | ID | Zone 1 (High) | 67/100 |
| 17 | 83203 | Fort Hall | ID | Zone 1 (High) | — |
| 18 | 83213 | Arco | ID | Zone 1 (High) | — |
| 19 | 83226 | Challis | ID | Zone 1 (High) | — |
| 20 | 83227 | Clayton | ID | Zone 1 (High) | — |
| 21 | 83229 | Cobalt | ID | Zone 1 (High) | — |
| 22 | 83235 | Ellis | ID | Zone 1 (High) | — |
| 23 | 83244 | Howe | ID | Zone 1 (High) | — |
| 24 | 83251 | Mackay | ID | Zone 1 (High) | — |
| 25 | 83253 | May | ID | Zone 1 (High) | — |
| 26 | 83255 | Moore | ID | Zone 1 (High) | — |
| 27 | 83278 | Stanley | ID | Zone 1 (High) | — |
| 28 | 83313 | Bellevue | ID | Zone 1 (High) | — |
| 29 | 83314 | Bliss | ID | Zone 1 (High) | — |
| 30 | 83320 | Carey | ID | Zone 1 (High) | — |
| 31 | 83322 | Corral | ID | Zone 1 (High) | — |
| 32 | 83327 | Fairfield | ID | Zone 1 (High) | — |
| 33 | 83330 | Gooding | ID | Zone 1 (High) | — |
| 34 | 83332 | Hagerman | ID | Zone 1 (High) | — |
| 35 | 83337 | Hill City | ID | Zone 1 (High) | — |
| 36 | 83348 | Picabo | ID | Zone 1 (High) | — |
| 37 | 83354 | Sun Valley | ID | Zone 1 (High) | — |
| 38 | 83355 | Wendell | ID | Zone 1 (High) | — |
| 39 | 83420 | Ashton | ID | Zone 1 (High) | — |
| 40 | 83421 | Chester | ID | Zone 1 (High) | — |
| 41 | 83423 | Dubois | ID | Zone 1 (High) | — |
| 42 | 83429 | Island Park | ID | Zone 1 (High) | — |
| 43 | 83433 | Macks Inn | ID | Zone 1 (High) | — |
| 44 | 83436 | Newdale | ID | Zone 1 (High) | — |
| 45 | 83438 | Parker | ID | Zone 1 (High) | — |
| 46 | 83445 | Saint Anthony | ID | Zone 1 (High) | — |
| 47 | 83446 | Spencer | ID | Zone 1 (High) | — |
| 48 | 83451 | Teton | ID | Zone 1 (High) | — |
| 49 | 83462 | Carmen | ID | Zone 1 (High) | — |
| 50 | 83463 | Gibbonsville | ID | Zone 1 (High) | — |
| 51 | 83464 | Leadore | ID | Zone 1 (High) | — |
| 52 | 83465 | Lemhi | ID | Zone 1 (High) | — |
| 53 | 83466 | North Fork | ID | Zone 1 (High) | — |
| 54 | 83467 | Salmon | ID | Zone 1 (High) | — |
| 55 | 83468 | Tendoy | ID | Zone 1 (High) | — |
| 56 | 83469 | Shoup | ID | Zone 1 (High) | — |
| 57 | 83520 | Ahsahka | ID | Zone 1 (High) | — |
| 58 | 83522 | Cottonwood | ID | Zone 1 (High) | — |
| 59 | 83525 | Elk City | ID | Zone 1 (High) | — |
| 60 | 83526 | Ferdinand | ID | Zone 1 (High) | — |
| 61 | 83530 | Grangeville | ID | Zone 1 (High) | — |
| 62 | 83531 | Fenn | ID | Zone 1 (High) | — |
| 63 | 83533 | Greencreek | ID | Zone 1 (High) | — |
| 64 | 83535 | Juliaetta | ID | Zone 1 (High) | — |
| 65 | 83536 | Kamiah | ID | Zone 1 (High) | — |
| 66 | 83537 | Kendrick | ID | Zone 1 (High) | — |
| 67 | 83539 | Kooskia | ID | Zone 1 (High) | — |
| 68 | 83542 | Lucile | ID | Zone 1 (High) | — |
| 69 | 83544 | Orofino | ID | Zone 1 (High) | — |
| 70 | 83546 | Pierce | ID | Zone 1 (High) | — |
| 71 | 83547 | Pollock | ID | Zone 1 (High) | — |
| 72 | 83549 | Riggins | ID | Zone 1 (High) | — |
| 73 | 83552 | Stites | ID | Zone 1 (High) | — |
| 74 | 83553 | Weippe | ID | Zone 1 (High) | — |
| 75 | 83554 | White Bird | ID | Zone 1 (High) | — |
| 76 | 83601 | Atlanta | ID | Zone 1 (High) | — |
| 77 | 83602 | Banks | ID | Zone 1 (High) | — |
| 78 | 83611 | Cascade | ID | Zone 1 (High) | — |
| 79 | 83615 | Donnelly | ID | Zone 1 (High) | — |
| 80 | 83622 | Garden Valley | ID | Zone 1 (High) | — |
| 81 | 83623 | Glenns Ferry | ID | Zone 1 (High) | — |
| 82 | 83627 | Hammett | ID | Zone 1 (High) | — |
| 83 | 83629 | Horseshoe Bend | ID | Zone 1 (High) | — |
| 84 | 83631 | Idaho City | ID | Zone 1 (High) | — |
| 85 | 83633 | King Hill | ID | Zone 1 (High) | — |
| 86 | 83637 | Lowman | ID | Zone 1 (High) | — |
| 87 | 83647 | Mountain Home | ID | Zone 1 (High) | — |
| 88 | 83657 | Ola | ID | Zone 1 (High) | — |
| 89 | 83666 | Placerville | ID | Zone 1 (High) | — |
| 90 | 83670 | Sweet | ID | Zone 1 (High) | — |
| 91 | 83671 | Warren | ID | Zone 1 (High) | — |
| 92 | 83677 | Yellow Pine | ID | Zone 1 (High) | — |
| 93 | 83716 | Boise | ID | Zone 1 (High) | — |
| 94 | 83801 | Athol | ID | Zone 1 (High) | — |
| 95 | 83802 | Avery | ID | Zone 1 (High) | — |
| 96 | 83803 | Bayview | ID | Zone 1 (High) | — |
| 97 | 83804 | Blanchard | ID | Zone 1 (High) | — |
| 98 | 83805 | Bonners Ferry | ID | Zone 1 (High) | — |
| 99 | 83806 | Bovill | ID | Zone 1 (High) | — |
| 100 | 83808 | Calder | ID | Zone 1 (High) | — |
Methodology
Radon rankings are based on EPA county-level radon zone classifications. Zone 1 (highest risk) has predicted average indoor radon levels above 4 pCi/L — the EPA action level. Zone 2 is moderate (2-4 pCi/L) and Zone 3 is low (below 2 pCi/L). Within Zone 1, ZIP codes are sub-ranked by Home Safety Score to prioritize areas with compounding risk factors.
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: 2026-08-14.
Frequently Asked Questions
What is EPA Radon Zone 1?
Zone 1 is the EPA highest-risk classification, meaning the county has predicted average indoor radon levels above 4 pCi/L — the level at which the EPA recommends mitigation. Radon causes about 21,000 lung cancer deaths per year in the U.S.
Should I test for radon?
The EPA recommends testing all homes regardless of radon zone. A DIY test kit costs $15-40. Professional testing costs $150-250. If levels exceed 4 pCi/L, mitigation systems ($800-2,500) can reduce radon by up to 99%.
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