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Buying and selling6 min read

Should I buy a house with radon?

By Radon411 Editorial TeamUpdated How we research

Short answer

You can buy a house with radon: a high level is a problem that can be fixed, usually with a vent pipe and fan system that costs about the same as other common home repairs. Get a valid test before you buy, and agree with the seller on when any fix happens and who pays.

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

Some radon reduction systems can cut levels by up to 99 percent, and where radon problems have been fixed, home sales have not been blocked or frustrated. The question for a buyer is not whether radon can be fixed but whether the level in this house is known.

Know the indoor radon level of any home you consider buying. You can accept the seller's earlier result after checking who did the test, where in the home it was taken and when, or ask for a new test by a qualified radon tester. A sale test should run for a minimum of 48 hours and include steps to prevent or detect interference with the device.

If the house already has a radon system, ask the seller for any information they have about it, and make sure the system is running during any test.

What to do next: schedule a radon test within your inspection period, write into the contract who pays for a fix if one is needed, and test again after any system is installed.

A radon problem is a fixable problem

Finding radon in a house you want to buy is not a reason on its own to walk away. Some radon reduction systems can cut levels by up to 99 percent, and in an existing home the cost to install a system is about the same as for other common home repairs. Where radon problems have been fixed, home sales have not been blocked or frustrated.

What a radon result means for a purchase
What you findWhat to do
No test on recordHave the home tested before you buy
A seller's test you can rely onAccept it after checking who did it, where and when
A high, confirmed resultAgree with the seller on when the fix happens and who pays
A radon system already in placeAsk for its records and test with the system running

The real risk for a buyer is not knowing. Radon levels can vary greatly from home to home, so a neighbor's result or an area's average says little about this house.

Testing a house before you buy

Know the indoor radon level of any home you consider buying. Because real estate sales happen quickly, there is often little time, and when you need results quickly, any of three short-term options is acceptable; each runs a minimum of 48 hours. The test goes in the lowest level that could be used regularly, since a buyer may choose to live in a lower area of the home 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: two tests at once, one after another, or a continuous monitor.

There is a potential for test interference in real estate transactions, so any sale test should include steps to prevent or detect it. Buyers frequently want tests made by someone who is not involved in the home sale, and a test by an independent, qualified radon tester is recommended. See should I get a radon test with my home inspection.

Using the seller's test result

You may accept an earlier result from the seller or ask for a new test by a qualified radon tester. Before you rely on the seller's test, check it the way you would check any other inspection report.

Questions to ask about a seller's radon test
AskWhy it matters
What was the result?The starting point for any decision
Who did the test: the homeowner, a radon professional or someone else?A qualified tester knows the proper conditions, devices and guidelines for a reliable result
Where in the home was it placed?A lower level you plan to use may not have been tested
When was it done?A test that is not recent, for example within two years, may call for a new one
Has the home changed since?A renovation or alteration since the test can change the level

If you accept the seller's test, make sure it followed the Radon Testing Checklist. If you decide a new test is needed, discuss it with the seller as soon as possible.

Writing radon into the contract

The purchase contract is where a radon test stops being a surprise. Consider including provisions that settle these points before anyone tests.

  • Where the test will be located
  • Who should conduct the test
  • What type of test to do, and when to do it
  • How the seller and the buyer will share the test results and test costs
  • When radon mitigation measures will be taken, and who will pay for them

If the house already has a radon system

A system in place points to a radon problem that was found and addressed. In most cases it is a vent pipe and fan, a system that does not require major changes to the home. Ask the seller for any information they have about the system, and if you test, make sure the system is working properly and running for the entire test.

Cross-section of a house with a sub-slab depressurization system: soil gas drawn from beneath the slab into a suction point, up a vent pipe, through a fan outside the living space and out above the roofline.
Read this figure as text
Sub-slab depressurization system in a house cross-sectionGround levelLiving spaceBasement12345
  1. Soil gas drawn from beneath the slab
  2. Suction point through the slab
  3. Vent pipe
  4. Fan, outside the living space
  5. Discharge above the roofline
A typical sub-slab depressurization system: suction under the slab, a vent pipe and a fan.

More on this case: should I buy a home with a radon mitigation system.

The health side of the decision

Radon matters because breathing in high levels over time may cause lung cancer; it is the second leading cause of lung cancer deaths in the United States after cigarette smoke. The upside for a buyer is that the risk responds to action: you will reduce your risk of lung cancer when you reduce radon levels, even if you have lived with an elevated level for a long time.

Questions about buying a house with radon

Is it safe to buy a house with radon?

A high radon level is a problem that can be fixed. Get a valid test, and if the level is high, agree with the seller on the fix before closing.

Who pays for radon mitigation when buying a house?

It is negotiated. The contract can say when mitigation will be done and who will pay for it.

Can I trust the seller's radon test?

Check who did it, where it was placed, when it was done and whether the home has changed since. If it does not hold up, ask for a new test by a qualified tester.

How long does a radon test take during a home sale?

Every radon test should run for a minimum of 48 hours. Two tests at the same time, two in a row, or a continuous monitor are the three short-term options.

Should I walk away from a house with high radon?

Not for radon alone. Where radon problems have been fixed, home sales have not been blocked or frustrated, and most homes can be fixed for about the same cost as other common home repairs.

What if the house has a radon system already?

Ask the seller for its records, and test with the system running to confirm it still works.

Buying and selling

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