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Buying and selling5 min read

Does radon testing affect a home sale?

By Radon411 Editorial TeamUpdated How we research

Short answer

It can shape the deal, but rarely ends it. A radon result becomes something buyer and seller negotiate: if levels are high, they discuss the timing and cost of a fix. Where radon problems have been fixed, home sales have not been blocked, and a documented fix can even help the sale.

Next step: see how a radon test fits a home sale. Testing for a home sale

Sellers do best testing before they list, which leaves time to fix a problem and keep the records. Buyers should know the level of any home they consider, from the seller's results or a new test.

The purchase contract can settle where and when the test is done, who does it, how results and costs are shared, and who pays for any fix. Some states also have disclosure rules.

What to do next: sellers, test before listing; buyers, write the radon test terms into the contract and use a qualified tester.

Where a radon test fits in a sale

A radon test is one more inspection item, and its result becomes something both sides can act on. Buyers often ask whether a home has been tested and whether high levels were reduced, so a sale is one of the most common moments for a test. The testing approach for sales is built around the short timelines of a purchase and the chance of interference with the test.

Radon testing at each stage of a sale
StageWhat happens
Before listingThe seller tests and, if needed, lowers the level, keeping the records
Offer and contractThe contract can set where, when and by whom the test is done, how results and costs are shared, and who pays for any fix
Inspection periodA qualified tester, often the home inspector, runs one of three short-term options
Result is highBuyer and seller discuss the timing and costs of radon reduction
After a fixA test confirms the level came down, ideally by an independent tester

For sellers: test before you list

Testing before the home goes on the market gives you time. If a problem turns up, you can fix it on your own schedule rather than inside a buyer's deadline. Keep the test results and everything about any fix: that record can be a positive selling point.

If you already tested, check that the test followed the testing checklist and give the results to the buyer. A buyer may still ask for a new test if the checklist was not met, the test is more than about two years old, the home was renovated since, or they plan to live on a lower level than was tested. More is in is it hard to sell a house with radon.

For buyers: know the level before you close

Know the indoor radon level of any home you are thinking of buying. Ask the seller for their results and, if the home has a radon system, for information about it. If it has never been tested, have it tested. The test belongs in the lowest level that could be used regularly, since a buyer may live lower in the house than the seller did.

EPA's three short-term radon testing options for a real estate transaction: two tests at the same time, one test then a second, or a continuous monitor, each for at least 48 hours, with what to do after each.
Read this figure as text

If you are testing in a real estate transaction and you need results quickly, any of the following three options for short-term tests are acceptable in determining whether the home should be fixed.

  1. Option 1. Two tests at the same time

    Passive

    Take two short-term tests at the same time in the same location for at least 48 hours.

    What to do nextFix the home if the average of the two tests is 4 pCi/L or more.

    Two tests taken at the same time (simultaneous) would improve the precision of this radon test.

  2. Option 2. One test, then a second

    Passive

    Take an initial short-term test for at least 48 hours. Immediately upon completing the first test, do a second test using an identical device in the same location as the first test.

    What to do nextFix the home if the average of the two tests is 4 pCi/L or more.

    One test followed by another test (sequential) would most likely give a better representation of the seasonal average.

  3. Option 3. A continuous monitor

    Active

    Test the home with a continuous monitor for at least 48 hours.

    What to do nextFix the home if the average radon level is 4 pCi/L or more.

    Both active and passive devices may have features which help to prevent test interference.

Any real estate test for radon should include steps to prevent or detect interference with the test device. Your state radon office can help you decide which option is best.

The three short-term testing options for a home sale, each at least 48 hours.

Buyers often want the test done by someone not involved in the sale. A qualified tester can provide that independent result. See should I get a radon test with my home inspection.

What to write into the contract

Radon terms to settle in the purchase contract
TermWhat to decide
LocationWhere the test device will go
TesterWho will run the test
Test typeWhich kind of test
TimingWhen the test will be done
Results and costsHow the seller and buyer will share the results and the cost of testing
MitigationWhen any radon fix will be done, and who will pay for it

The guidance does not say which side should pay; that is for the buyer and seller to agree. In some areas, companies offer service agreements with a one-time fee covering both testing and any needed; your state radon office can say whether they exist where you are.

Keeping the test fair

A sale is where test interference is most likely, so testers guard against it. Disturbing a test device or the can invalidate the result and is illegal in some states.

Ways testers prevent or detect interference
SafeguardWhat it shows
A device that records levels frequentlyUnusual swings during the test
Barometric pressure recordsWeather that may have affected the test
Temperature recordsWhether doors and windows were opened
A signed non-interference agreementThe seller or occupant agreed not to disturb the test

Deliberate tampering is covered in how a radon test can be manipulated.

State rules on radon in a sale

Disclosure rules vary by state, and a buyer may ask for a new test where the state or local government requires radon information to be disclosed. Some examples show the range.

Examples of state radon rules for home sales
StateRule
IllinoisThe seller must give the buyer a state radon pamphlet and a Disclosure of Information on Radon Hazards
New JerseyAt contract, the seller must give the buyer the radon test results and evidence of any mitigation; only state-certified companies may test or mitigate, except owners in their own homes
UtahThe seller's disclosure form asks about hazardous conditions, including radon

Your state radon office can tell you what applies; see the state radon programs list and the radon disclosure guide.

Questions about radon and home sales

Does a high radon test kill a home sale?

Not usually. A high result is a repair item for buyer and seller to discuss, and where radon problems have been fixed, sales have not been blocked.

Who pays for radon mitigation when selling a house?

It is negotiated. The contract can state when a fix will be done and who will pay; the guidance does not assign it to either side.

Should a seller test for radon before listing?

Yes. Testing before listing gives you more time to deal with a problem, and records of a fix can help the sale.

Can a buyer ask for a new radon test?

Yes, especially if the earlier test missed checklist items, is more than about two years old, came before renovations, or was on a higher floor than the buyer will use.

Does a radon system lower a home's value?

A system shows a problem was fixed, and the added protection can be a selling point. See does a radon mitigation system hurt resale.

Who should do the radon test in a sale?

A qualified tester, very often a home inspector, who can provide an independent result.

Buying and selling

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Radon in a home sale: testing before closing, the inspection, disclosure and negotiation.

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