Radon Mitigation Cost in New Hampshire (2026)

Radon in New Hampshire

The nickname says it all. New Hampshire's granite bedrock — the same rock that defines the White Mountains — releases radon throughout the state. NH is predominantly EPA Zone 1 (highest risk), and testing rates consistently show elevated levels across Hillsborough, Merrimack, Rockingham, Cheshire, and Sullivan counties.

Southern New Hampshire (Manchester, Nashua, Concord, and the Boston-commuter suburbs) has heavy housing density and some of the highest radon testing activity in New England. If you bought a southern NH home in the last decade, there's a good chance a test was already done — dig up those records.

Cost by Foundation Type

Finished Basement: $1,100–$2,500

The predominant foundation type in New Hampshire. Colonial, Cape Cod, and Ranch homes throughout southern NH almost universally have basements.

• Unfinished basement: $1,100–$1,600
• Partially finished: $1,400–$2,000
• Fully finished, complex routing: $1,800–$2,500

Crawl Space: $2,500–$5,500

Older New Hampshire homes — particularly 18th and 19th century farmhouses and capes — often have partial crawl spaces or fieldstone foundation perimeters. These present unique challenges.

• Crawl space with modern encapsulation: $2,500–$4,000
• Stone foundation perimeter, difficult access: $3,500–$5,500+

Slab-on-Grade: $1,000–$1,900

Found in 1960s–1990s ranch-style homes and newer construction. Less common in NH than basement construction.

New Hampshire-Specific Cost Factors

Granite geology: High-radon geology means NH homes can test very high (15–40+ pCi/L in worst cases). Multiple suction points or premium fans may be needed — add $400–$900.

Well water radon: New Hampshire has one of the highest rates of private well usage in the country, and radon in well water is a real concern. If you're on a well and have elevated air readings, ask about water testing. Water treatment is a separate system ($2,000–$5,000+).

Regional labor costs: New Hampshire contractors charge roughly 15–25% more than national averages for equivalent work. Southern NH's proximity to Boston's labor market influences rates.

Old stone foundations: Pre-1900 NH homes with fieldstone foundations require specialized approaches — sub-slab depressurization isn't always possible. Experienced contractors will assess and recommend alternative approaches (sub-membrane depressurization, block wall depressurization, or increased ventilation).

New Hampshire Resources

• NH Dept of Environmental Services Radon Program: des.nh.gov/radon
• Verify NRPP: radonproficiency.org
• Verify NRSB: nrsb.org

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