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State overview
Radon in Maine
Of Maine's 16 counties and county equivalents, EPA places 12 in Zone 1, 4 in Zone 2. Zones are county-wide predictions; testing is the only way to know your home's level.
Radon in the news
Maine stories
- Some Maine schools have unsafe radon levels. Most haven’t been tested.Portland Press Herald - Maine Sunday Telegram · 2026-05-05
- Maine CDC Data Shows What Towns Are at Higher Risk For Radon in the Air94.9 HOM · 2025-01-30
- Maine Radon 2024American Lung Association · 2024-01-09
- Invisible invader: Radon testing recommended in Maine homesThe Ellsworth American · 2023-04-06
- Have you tested your water for radon? Maine lawmaker says you shouldn't wait any longerSeacoastonline.com · 2022-01-21
Headlines link to the original publishers via Google News. Updated 2026-10-27.
All 16 counties
| County | EPA zone |
|---|---|
| Androscoggin County | Zone 1 |
| Aroostook County | Zone 1 |
| Cumberland County | Zone 1 |
| Franklin County | Zone 1 |
| Hancock County | Zone 1 |
| Kennebec County | Zone 1 |
| Knox County | Zone 2 |
| Lincoln County | Zone 1 |
| Oxford County | Zone 1 |
| Penobscot County | Zone 1 |
| Piscataquis County | Zone 1 |
| Sagadahoc County | Zone 2 |
| Somerset County | Zone 1 |
| Waldo County | Zone 2 |
| Washington County | Zone 2 |
| York County | Zone 1 |
Source: EPA radon zones spreadsheet (EPA 402/A-16/001).