We routinely get requests from past home inspection clients of ours asking us to re-send the radon gas test results from testing that we conducted many years ago. We get these requests because our past clients are now selling their home, and they’re performing their due diligence attempting to gather whatever information they can about their home to give to potential home buyers. In most cases, we still have the results and are happy to send them out. We recently received an email asking about this:
"Two months ago the seller had another buyer inspect the home. The radon test came back at 1.8. Does this need to be done again? Thanks!"
That's a great question. Here's my generic advice on relying on the seller's test results.
Over Two Years Old? Forget it.
How much value is there in old radon test results? If the test results are more than two years old, the EPA recommends conducting a new test. If the test results are less than two years old, there might be some value in those results.
Who Conducted the Previous Radon Test?
If the test results are less than two years old, find out who conducted the radon test before relying on the results. For obvious reasons, I don’t recommend relying on any type of DIY radon tests unless you Did It Yourself. If the radon test was professionally conducted, make sure the person / company conducting the test was qualified to do so. You’d hope that any home inspector charging money to conduct a radon test would be qualified to perform the test and would do it properly, but I’ve personally seen enough egregious testing errors to know that there are plenty of unqualified folks conducting radon tests in Minnesota. While there are no licensing requirements for radon testing companies in Minnesota, there are two large certifying bodies for radon measurement providers: the National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB). I’d feel fairly confident in relying on the radon gas test results from an NRPP or NRSB certified company. That’s not to say that you shouldn't rely on the results from someone who isn't certified, but you’d be right to at least ask a few questions about the qualifications and experience of the person / company doing the testing.
Has Anything Changed?
If there have been any major structural changes, HVAC changes, or there have been any significant projects that involved air sealing, which is most commonly done in the attic, don’t go with the old test results. Too much has changed that may have affected the radon levels. Have your own test conducted.
Where Was The Test Placed?
When a homeowner conducts a radon test on their own home, they’re supposed to test the lowest level of the home that is regularly used. If the home has an unfinished basement and nobody spends any time down there, the test should be placed on the first floor. When a radon test is conducted as part of a real estate transaction, the radon test should be placed in the lowest livable part of the home, whether it’s finished or not. If a home buyer is going to rely on the seller’s radon test results, they should make sure the test was placed in the lowest livable area, not the lowest level that is regularly used.
If a home buyer is going to rely on someone else's radon test results instead of hiring their own company to conduct a radon test, they should make sure that the previous test was done within the last two years, the testing was done by a qualified person / company, no major changes happened at the home that could affect radon levels, and that the radon test was placed in the proper location.