Out of 32 ZIP codes with data in New Hampshire, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes with Highest Radon Risk | All New Hampshire Rankings
| Statistic | Value |
|---|---|
| ZIP codes ranked | 32 |
| Lowest value | Zone 1 (High) |
| Median value | Zone 1 (High) |
| State | New Hampshire |
32 Lowest-Ranked ZIP Codes
| Rank | ZIP Code | City | State | Radon Zone | Safety Score |
|---|---|---|---|---|---|
| 1 | 03840 | Greenland | NH | Zone 1 (High) | 67/100 |
| 2 | 03227 | Center Sandwich | NH | Zone 1 (High) | — |
| 3 | 03254 | Moultonborough | NH | Zone 1 (High) | — |
| 4 | 03259 | North Sandwich | NH | Zone 1 (High) | — |
| 5 | 03812 | Bartlett | NH | Zone 1 (High) | — |
| 6 | 03813 | Center Conway | NH | Zone 1 (High) | — |
| 7 | 03814 | Center Ossipee | NH | Zone 1 (High) | — |
| 8 | 03816 | Center Tuftonboro | NH | Zone 1 (High) | — |
| 9 | 03817 | Chocorua | NH | Zone 1 (High) | — |
| 10 | 03818 | Conway | NH | Zone 1 (High) | — |
| 11 | 03830 | East Wakefield | NH | Zone 1 (High) | — |
| 12 | 03832 | Eaton Center | NH | Zone 1 (High) | — |
| 13 | 03836 | Freedom | NH | Zone 1 (High) | — |
| 14 | 03838 | Glen | NH | Zone 1 (High) | — |
| 15 | 03845 | Intervale | NH | Zone 1 (High) | — |
| 16 | 03846 | Jackson | NH | Zone 1 (High) | — |
| 17 | 03847 | Kearsarge | NH | Zone 1 (High) | — |
| 18 | 03849 | Madison | NH | Zone 1 (High) | — |
| 19 | 03850 | Melvin Village | NH | Zone 1 (High) | — |
| 20 | 03852 | Milton Mills | NH | Zone 1 (High) | — |
| 21 | 03853 | Mirror Lake | NH | Zone 1 (High) | — |
| 22 | 03860 | North Conway | NH | Zone 1 (High) | — |
| 23 | 03864 | Ossipee | NH | Zone 1 (High) | — |
| 24 | 03872 | Sanbornville | NH | Zone 1 (High) | — |
| 25 | 03875 | Silver Lake | NH | Zone 1 (High) | — |
| 26 | 03882 | Effingham | NH | Zone 1 (High) | — |
| 27 | 03883 | South Tamworth | NH | Zone 1 (High) | — |
| 28 | 03886 | Tamworth | NH | Zone 1 (High) | — |
| 29 | 03890 | West Ossipee | NH | Zone 1 (High) | — |
| 30 | 03894 | Wolfeboro | NH | Zone 1 (High) | — |
| 31 | 03896 | Wolfeboro Falls | NH | Zone 1 (High) | — |
| 32 | 03897 | Wonalancet | NH | 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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