Alton is located in Belknap County, New Hampshire.
With 2 user-submitted readings averaging 8.00 pCi/L,
the area exceeds the EPA's 4.0 pCi/L action threshold, and testing is strongly recommended for homeowners in the 03809 zip code.
8.00
pCi/L average
Above EPA Action Level
Based on 2 user-submitted radon tests for homes in Alton, NH. The EPA recommends taking action at or above 4.0 pCi/L.
0
4.0 EPA
10+
Alton, NH Radon Mitigation
Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.
Alton, NH Radon Testing
Finding qualified radon testing professionals is the first step toward protecting your home.
Alton, New Hampshire Radon Levels
User-submitted radon test readings from homes in the Alton area.
Radon Level
City
Home Age
Foundation
Submitted
8 pCi/L
Alton, NH
0-20 Years
Full Basement
May 2025
Have a radon test result for Alton? Submit your reading to help other homeowners.
Alton Radon Facts
Key details about the radon risk profile for Alton and the 03809 zip code area.
EPA Radon Zone
Zone 2 — Moderate Risk
County
Belknap County, NH
Zip Code
03809
Predicted Screening Level
2–4 pCi/L (Zone 2)
Avg. User Submitted Level
8.00 pCi/L
User Tests Submitted
2
Alton and the 03809 zip code are located in Belknap County, which has an EPA assigned Radon Zone of 2. A radon zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L. The EPA recommends testing every home regardless of zone classification.
Radon FAQ for Alton, NH
What is the average radon level in Alton, NH?
Based on 2 user-submitted tests, the average radon level in Alton is 8.00 pCi/L. This exceeds the EPA's recommended action level of 4.0 pCi/L, and radon testing is recommended for all homes in the area.
What EPA Radon Zone is Alton in?
Alton and the 03809 zip code are in Belknap County, which has an EPA assigned Radon Zone of 2. A zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L.
How much does radon mitigation cost in Alton?
Radon mitigation in Alton typically costs between $800 and $2,000. Most homes with standard basements can be mitigated with a sub-slab depressurization system in the $1,000–$1,500 range. Factors that can increase cost include complex foundations, crawl spaces, or very high radon levels.
Should I test for radon if I'm buying a home in Alton?
Yes. Radon testing should be part of every home purchase. A short-term radon test is typically included as part of the home inspection process and costs $150–$250. If elevated levels are found, you can negotiate mitigation as part of the sale.
Most Active Radon Markets in New Hampshire
Cities with the most user-submitted radon test data in the state.
