If you're buying a house in Minnesota and you want to have it tested for radon as part of your inspection contingency, here's a list of six items that the EPA says you should consider before you have the test conducted.
Where the radon test will be located
The radon test should be placed in the lowest level of the home that could be used regularly, whether it's finished or not. I've said before that radon tests should never be placed in crawl spaces, but what if the basement ceiling height is 6' 11" ? The Minnesota State Building Code defines a crawl space as "Areas or rooms with less than 7 feet ceiling height measured to the finished floor or grade below.” (MN Rules 1309.0202) This is a grey area that should be discussed ahead of time.
Who should conduct the radon test
What type of radon test to do
A radon test performed with a continuous electronic monitor can be completed in as little as 48 hours. The other type of test that is most commonly used for a real estate transaction is a charcoal canister test. This type of test must remain in the home for minimum of 72 hours, and then the canisters must be sent to a lab for analysis. Do you have time to get the testing completed?
When to do the radon test
The occupant of the home must maintain closed house conditions for 12 hours prior to, and throughout the duration of the radon test. This means keeping windows and doors closed, except for normal traffic. A few things that make this difficult would be if the seller is moving, if the home is under construction, if it's new construction, or it's a hot week in August and the home doesn't have air conditioning. Stuff to think about...
How the seller and the buyer will share the radon test results and test costs
The issue over the test costs is a no-brainer; if the buyer wants a test, they should pay for it. If the seller doesn't want to know about the test results, they should make that clear ahead of time. Whywouldn't the seller want to know? If the test is high, this must now be disclosed to any future buyers if the deal falls apart for any reason.
When radon mitigation measures will be taken, and who will pay for them.
This is the big one. Ideally this would be decided ahead of time, but I've never heard of this actually happening. If the radon test comes up high, most home buyers will ask the seller to install a mitigation system, but will the seller be willing to do this?
While I'm certainly an advocate of radon testing, one of the few times that I don't recommend testing for radon at the time of a home purchase is when the results aren't going to make any difference. In other words, if the buyer has decided to purchase a home regardless of the radon levels and the seller is unwilling to mitigate high levels of radon, there's no point in having a professional test performed ahead of time. The buyers would be just as well off performing a long-term test on their own after they purchase the house.
Reuben Saltzman, Structure Tech Home Inspections