Radon for home buyers and sellers
Radon comes up in a lot of Billings home sales. Here's what Montana law asks of sellers and how to handle a test on a deadline.
Montana doesn't require a radon test to sell a house. It does require disclosure. Under Montana Code 75-3-606, the seller or the seller's agent has to give the buyer a standard radon warning in a document signed before or with the offer, stating that radon levels above federal guidelines have been found in Montana buildings. If the seller knows the building was tested, they must hand over the results and any proof of mitigation.
For buyers
- The EPA recommends that buyers test every home, regardless of zone, usually during the inspection period.
- If the house already has a system, ask for the installer's paperwork and the latest test, and look for a running fan and a manometer showing suction.
- At 4 pCi/L or higher, the EPA recommends negotiating mitigation with the seller. You might ask for a system before closing, a credit, or plan to install one yourself after.
- Under the statute, the seller's disclosure doesn't create a right to back out unless your contract says so, so talk to your agent about a radon contingency.
For sellers
- Testing before you list avoids a surprise in the middle of the inspection window.
- If you've tested before, Montana law says you have to share the results, so keep them on file.
- If you install a system, keep the installer's details, certification and the post-mitigation result.
How are real estate tests done?
Most are short-term tests with a continuous monitor under closed-house conditions. Opening windows, running a whole-house fan or moving the monitor can skew the result, and many monitors log tampering. Keep the house shut and leave the device alone.
Can it all happen before closing?
Often, if you call early. Give the radon company your inspection deadline and closing date up front so they can schedule the test, the install and the follow-up test in order.
The radon company sets the price after it learns about your house, and usually after someone has looked at the foundation. We don't quote prices, and a number given over the phone is only a rough starting point.
Where we connect you with help
Common questions
Does Montana require a radon test when selling a house?
No. Montana requires sellers to give a radon disclosure warning and to share any known test results and mitigation records, but it doesn't require a test.
Who pays for mitigation in a sale?
It's negotiated. Sellers often install a system or give a credit after a high buyer's test. Your agent can advise you.
Related services
More background: Montana radon guide.
Got a radon number you don't like?
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