A radon problem in Massachusetts does not stop a sale, and it does not have to delay one either. Radon is a radioactive gas that comes up naturally from soil and rock, and the only way to know whether a given house has it is to test for it, since you cannot see it, smell it, or taste it. Massachusetts has no law requiring a seller to test for radon or to disclose a result the way the state requires for lead paint. What actually happens next depends on the number on the test, what the buyer’s lender needs to see, and whether you would rather mitigate, disclose, or sell the house as is.
Step One: Test the House, Because Guessing Doesn’t Work
Any home can have elevated radon, regardless of its foundation type, its age, or whether the basement is finished. The Massachusetts Department of Public Health’s Radon Unit, part of the Indoor Air Quality Program, recommends every home get tested, and a short-term test kit from a hardware store or online is the usual starting point. If you want the result to hold up in a negotiation, hire a measurement professional certified by the National Radon Safety Board or the National Radon Proficiency Program instead of relying on a kit alone. Massachusetts does not license radon professionals itself, so the certification is what you are checking for, not a state number.
Timing matters more than most sellers expect. Radon levels run higher in winter, when a closed-up house exchanges less air, so a test run between November 1 and March 31 is the window state guidance treats as reliable. A summer test that comes back low is not necessarily telling you the truth about January.
Results are measured in picocuries per liter, written as pCi/L. Outdoor air runs around 0.4 pCi/L, and no house will ever read zero. The U.S. Environmental Protection Agency sets 4 pCi/L as the national action level, the point at which it recommends fixing the problem, and it suggests considering action even between 2 and 4 pCi/L, since no level is entirely risk-free.
| Result | What it generally means |
|---|---|
| Under 2 pCi/L | At or near typical background levels |
| 2 to 4 pCi/L | EPA says consider mitigation, not required |
| 4 pCi/L or higher | EPA action level, mitigation generally recommended |
What a Radon Problem in Massachusetts Means for a Sale
Here is the part that surprises people who already went through a lead paint disclosure on an older house. Massachusetts requires sellers to give buyers the Property Transfer Notification for lead paint before the purchase and sale agreement is signed, with no construction year threshold. There is no equivalent statute for radon. A seller is not required to test, and is not required to let a buyer’s inspector test either, though in practice almost every buyer who orders a general inspection adds a radon test as a line item, since it is usually a modest add-on rather than a separate appointment.
That does not mean a known result can simply be ignored. If you already have a test in hand showing an elevated number, saying nothing when asked directly, or describing the house in a way that contradicts what you know, is a different problem from radon itself, since general misrepresentation exposure under Massachusetts consumer protection law does not depend on there being a radon-specific statute. If an earlier buyer walked away from the deal specifically over a radon result, that is the kind of fact a listing agent typically has to disclose to the next one. None of this is a reason to panic. It is a reason to be straightforward about whatever you actually know and let the buyer decide what to do with it.
Does a High Radon Reading Kill Your Financing?
Generally, no, not by itself. Neither the FHA nor the VA loan programs require a radon test as a condition of approving a loan on an existing single-family home, so an appraiser is not going to flag it the way a missing smoke detector certificate or a structural crack would. EPA’s guidance for the real estate community treats radon as a buyer and seller negotiation, not a financing checklist item. In the deals we have closed, the reliable mortgage killers are major structural or safety defects, the kind an appraiser can see and has to account for, not an environmental reading that is not part of the appraisal protocol in the first place. An ordinary house still finances if a lender’s appraiser can call it safe and habitable. A buyer can still ask for a radon contingency in the purchase and sale agreement, and plenty do, but that is a negotiated term between the parties, not a lending requirement working against you.
Step Three: Mitigate, Disclose, or Sell As Is
Once you have a real number, there are three honest paths, and the right one depends on how much time and certainty you want to spend.
- Mitigate it. A sub-slab depressurization system is the standard fix, installed by a contractor certified the same way the testers are. National cost guides commonly put a typical system somewhere in the $800 to $2,500 range, with the real number driven by the house’s foundation and how the contractor has to route the vent pipe. Once installed, a mitigation system needs to be retested every year or two to confirm it is still doing its job.
- Disclose the number and sell anyway. Many buyers, especially ones already planning renovations, will take the house with a known reading and either live with it or mitigate it themselves after closing. This usually shows up as a modest price adjustment rather than a dealbreaker.
- Sell to a buyer who is not ordering a radon test at all. A cash purchase that skips a financed buyer’s inspection and appraisal contingencies also skips the radon line item that would otherwise show up on that inspection. This is not a way to hide a known problem, which brings you back to the disclosure point above, but it does mean the sale is not waiting on a mitigation contractor’s schedule.
What This Looks Like If You Just Want the Sale Done
If a radon number is the thing standing between you and a closing date, you do not need to become an expert in sub-slab depressurization to sell the house. Selling a house with UFFI insulation in Massachusetts runs into the same pattern: an older-home condition that sounds alarming, is not actually a disclosure violation by itself, and does not have to be fully resolved before you can sell. If you would rather skip the testing, the contractor scheduling, and the retest a year later, get a cash offer for your Massachusetts house and let the next owner decide what to do about the number.
The Massachusetts Radon Hotline, (800) 723-6695, is the state’s own number for testing and mitigation questions, and it is free to call before you commit to anything.
Homeowners We’ve Helped
Boston Investors
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After 94 days on the market, two buyers backed out over the roof and septic. We were tired of dealing with it. The cash offer came without asking us to make the repairs, and we closed in 21 days. Once we looked at the actual numbers, it made much more sense than continuing to list. The whole process was simple and we’re very happy with how it worked out.
