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Radon in a Home Sale: Steps for Buyers and Sellers
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If you are selling
- Test before you list, if you can. Test in the lowest level of the home that could be used regularly, including a lower level a buyer might use as a family room or play area.
- Already tested? Check the test against EPA's Radon Testing Checklist. If it was done correctly, give the results to the buyer.
- Expect a new test request if the last test is not recent (EPA's example is within two years), you have renovated since, the checklist was not followed, or the buyer plans to use a lower level than you tested.
- If it is high, fix it first. EPA says correcting a problem before listing gives you more time. Keep the test results and records of the fix.
- Check disclosure rules. A buyer may ask for a new test if your state or local government requires disclosure of radon information. Ask your state radon program.
If you are buying
- Ask for the seller's results, and any information about an existing radon system.
- Before accepting a seller's test, find out the results, who did the test, where in the home it was taken, and any structural or HVAC changes since.
- Test where you will live. If you plan to use the basement as living space, test there.
- Put the details in the contract. EPA lists: where the test will be located, who conducts it, what type of test, when, how results and costs are shared, and when mitigation will be done and who will pay.
- Planning to finish a basement? EPA says to test before the project and after. It is generally less expensive to install a radon system before or during renovations than afterward.
The three short-term options EPA accepts in a sale
| Option | What to do next |
|---|---|
| Two passive short-term tests at the same time, same location, at least 48 hours | Fix the home if the average of the two tests is 4 pCi/L or more. |
| One passive short-term test of at least 48 hours, then right away a second test with an identical device in the same location | Fix the home if the average of the two tests is 4 pCi/L or more. |
| One continuous monitor test of at least 48 hours | Fix the home if the average radon level is 4 pCi/L or more. |
Source: EPA, Home Buyer's and Seller's Guide to Radon. If time permits (more than 90 days), a long-term test can confirm a short-term result; EPA says to fix at 4 pCi/L or higher on a long-term test.
Prevent test interference
EPA says interference is a real risk in sales. It lists these ways to prevent or detect it: a device that records radon often, a motion detector, a proximity detector, recording barometric pressure and temperature, tamper-proof seals on windows and a non-interference agreement signed by the seller or occupant. Ask a qualified radon tester about them. Moving the device or breaking closed-house conditions can invalidate the result.
New homes
EPA says to ask the owner or builder if a new home has radon-resistant features, and to test every new home after move-in even if it was built radon-resistant. If the result is 4 pCi/L or more, a vent fan can be added to the passive system.
Need a test for the sale?
Testing is the only way to know your radon level. A mail-in kit is a low-cost way to start, and our guide shows how to place it so the result is reliable.
How to use a radon test kitBrowse radon test kitsRadon came back high during the sale?
EPA says to hire a qualified, certified radon mitigation contractor and to get more than one estimate. Start with your state radon program, then compare written quotes.
How to find a certified contractorCompare local radon prosCommon questions
Should I test before I list my home?
EPA recommends it. It says to test before putting the home on the market and, if necessary, lower the radon level, then save the test results and any records of the fix. EPA says this could be a positive selling point.
Can a radon problem block a sale?
EPA says where radon problems have been fixed, home sales have not been blocked or frustrated, and the added protection is sometimes a good selling point. Michigan's EGLE says a buyer can have the home fixed before or after purchase with equal confidence of success, and that there is no need to walk away from a home you want.
Who pays for the fix?
EPA says the buyer and seller should discuss the timing and costs. It suggests the sales contract say how test results and test costs are shared, and when mitigation will be done and who will pay.
Can the same company test and fix it?
EPA warns of a potential conflict of interest if the same person or firm performs the testing and installs the system. Some states may require a waiver. If the same firm does both, make sure the testing follows EPA's Radon Testing Checklist.
Related guides
- What does my radon test result mean?
- Radon mitigation cost
- Find a certified contractor
- Radon test kits
- Digital radon detectors vs test kits
Free printable: Radon Test Day Checklist
EPA's testing steps in one page, plus what your result means. Download the one-page PDF now, or get it by email along with a short series of five helpful emails.