High Radon in Your Massachusetts House? Testing and Fixes
Radon is an invisible, odorless gas from soil that can build up in basements, and testing is the only way to know your level. Massachusetts estimates about one in four homes may be above the EPA action level of 4 pCi/L, and high readings are found in every county. Most homes can be fixed with a sub-slab mitigation system for around $800 to $1,300.
What to look for
- No visible signs; only a test shows radon
- A short-term test at or above 4 pCi/L
- Home inspection radon result flagged during a sale
- Private well (water should be tested for radon too)
What it costs
| What | Typical cost | Source |
|---|---|---|
| Radon mitigation system (national average) | $800 to $1,300; complex homes up to $2,500 | angi.com |
| Radon test (national average) | $15 to $200 | angi.com |
| Post-mitigation verification test (national average) | $50 to $200 | angi.com |
Ranges are published estimates; your quote depends on the house. Get two or three written quotes.
Massachusetts rules to know
- The Massachusetts Department of Public Health uses the EPA action level of 4 pCi/L and suggests considering mitigation from 2 to 4 pCi/L; it estimates about 650,000 Massachusetts homes are above 4 pCi/L (source: mass.gov)
- DPH says high radon is found in every county, and homes with private wells should also have the water tested for radon (source: mass.gov)
- DPH recommends testing between November and March, and using professionals certified by AARST/NRPP or the National Radon Safety Board (mass.gov; mass.gov)
- The DPH Radon Information Line is 800-723-6695 (source: mass.gov)
Who to call
- A radon measurement or mitigation professional certified by AARST/NRPP or NRSB; DPH posts lists of certified pros (source: mass.gov)
- The MA DPH Radon Unit at 800-723-6695 for questions (source: mass.gov)
- A well-water lab if you have a private well
- If you're worried about health effects, see a doctor
DIY or hire a pro?
Testing is easy to do yourself with a short-term kit from a hardware store or online. Mitigation systems should be installed by a certified radon mitigation professional.
If fixing it is more than you want to take on
Radon usually isn't a deal-breaker because mitigation is fairly cheap, so installing a system or giving a credit is common. You can also sell as-is and let the buyer handle it, or sell to a cash buyer. Radon alone rarely justifies a cash sale, but it can be one more item when a house has several problems.
Want a cash offer on the house as it is?
Western Mass Cash Home Buyers buys houses as-is across Western Massachusetts: no repairs, no cleanout, no fees. You pick the closing date.
Common questions
Is radon testing required to sell a house in Massachusetts?
Massachusetts doesn't require a radon test at sale, but many buyers test during the home inspection.
What radon level is safe in Massachusetts?
DPH uses the EPA action level of 4 pCi/L and suggests considering mitigation between 2 and 4 pCi/L.
How much does radon mitigation cost?
Nationally most systems cost $800 to $1,300, with larger or complex homes up to about $2,500.
Is radon common in Western Massachusetts?
DPH says high radon levels are found in every Massachusetts county, so every home should be tested.
When is the best time to test for radon?
Massachusetts recommends testing between November and March, with windows and doors closed for at least 12 hours before.
Related guides: Mold · Asbestos · Lead paint · Termites & pests · Foundation problems · Roof replacement · all house problem guides
Sources
Checked September 2026: mass.gov · mass.gov · mass.gov · angi.com · nolo.com
General information, not legal, tax, medical or engineering advice. Rules and prices change; confirm with the agency or a licensed professional.