2026-02-15 · 5 min read
Radon Mitigation Cost in Maine (2026)
Maine's granite bedrock earns it a spot among the top radon states in the Northeast. Mitigation costs $1,100–$2,600, with well water radon a secondary concern for rural homes.
Radon in Maine
Maine is granite. The New England Batholith — the same rock formation that defines New Hampshire and Vermont — underlies most of Maine's interior. Combined with the state's old, tight housing stock built for brutal winters, Maine has one of the highest rates of elevated radon readings in the Northeast.
Androscoggin, Kennebec, Somerset, Piscataquis, Penobscot, and Aroostook counties are predominantly Zone 1. The coastal strip (Cumberland, Knox, Lincoln, Waldo) runs Zone 2. No part of Maine should be considered low-risk without testing.
Cost by Foundation Type
Finished Basement: $1,100–$2,500
Maine's climate means virtually all homes have basements. Most are unfinished or partially finished.
- Unfinished basement: $1,100–$1,700
- Partially finished: $1,500–$2,200
- Fully finished, complex routing: $1,900–$2,500
Crawl Space: $2,800–$5,500
Older Maine farmhouses and Capes frequently have crawl spaces, often with stone foundation perimeters and rocky soil.
Slab-on-Grade: $1,000–$1,900
Less common in Maine's older housing stock, but found in some 1970s–2000s construction near Portland and Bangor.
Maine-Specific Factors
Well water radon: Maine has one of the highest rates of private well usage in the country. If you're on a well and your air radon is elevated, the Maine CDC recommends testing your water as well. Water radon mitigation is a separate system.
Old housing stock: Many Maine homes are pre-1950 with stone foundations. These require specialized assessment before standard depressurization can be applied.
Rural contractor shortage: Outside Portland, Lewiston-Auburn, and Bangor, certified contractors are scarce. Budget extra time for scheduling.
Winter testing: Maine's heating season (depressurization effect increases indoor radon) makes fall and winter tests most representative of average exposure.
Maine Resources
- ME CDC Radon Program: maine.gov/dhhs/mecdc (search "radon")
- Verify NRPP: radonproficiency.org
- Verify NRSB: nrsb.org
Frequently Asked Questions
How bad is radon in Maine?
Maine is a high-radon state. Most of Maine sits on the New England Batholith — a massive granite formation running from Massachusetts through Maine. The state is predominantly EPA Zone 1 inland and Zone 2 along the coast.
How much does radon mitigation cost in Maine?
Expect $1,100–$2,300 for basement homes and $2,800–$5,500 for crawl spaces. Maine contractor rates are above national averages, similar to other northern New England states.
Is radon in well water a concern in Maine?
Yes — Maine has high rates of private well use and granite bedrock that can dissolve radon into groundwater. If you're on a well and have elevated air readings, ask about water testing as well. Radon in water requires a separate treatment system.
Find a Certified Mitigator Near You
Every contractor on RadonBase is NRPP or NRSB certified — mitigators only, no testers.
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