Promoting and protecting the health and safety of all Idahoans

Frequently Asked Questions About Radon

Click on the questions below to learn more about radon. 

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Radon is a naturally occurring radioactive gas that comes from the breakdown of uranium in the soil.  It is a colorless, odorless, tasteless and invisible gas.

Radon levels are measured in picocuries per liter of air or pCi/L.

Radon is the leading cause of lung cancer in nonsmokers. The Environmental Protection Agency (EPA) estimates that radon causes 21,000 lung cancer deaths each year in the U.S. The risk of developing lung cancer from radon depends on the level of radon you are exposed to over a lifetime, as well as other genetic and environmental factors, such as if you are a smoker.

Long-term exposure to high radon levels can increase your risk of developing lung cancer.  When radon gas decays, it breaks down into radioactive particles that can get trapped in your lungs when you breathe.  As the particles continue to decay, they release small bursts of energy that can damage lung tissue and may lead to lung cancer in some people. 

Yes, there are many areas throughout Idaho that have high levels of radon. For more information on radon levels where you live, call the Idaho Department of Health and Welfare’s Indoor Environment Program at 1-800-445-8647.


View a map of elevated radon test results in Idaho. 

Testing is the only way to know if you and your family are at risk from radon. There are two general tests for radon:  short-term and long-term. The quickest way to test is with a short-term test.  These tests provide a quick radon value within a brief period (typically three to seven days) of time.  Long-term tests are typically placed in the home for at least three months and may remain in the home for up to a year. Long term test kits give a better estimate of the amount of radon in your home throughout the year. 

You can purchase radon test kits from hardware stores, home improvement centers, online or other retail outlets.  Reduced price short-term radon test kits may be purchased by Idaho residents from Air Chek

A common radon test kit comes in a small cardboard packet like the example shown below.


Preferably test your home for radon in the winter. Your test should be performed on the lowest floor of your home where you spend time.  If you have a basement and spend time there, test in the basement.  Otherwise, test on the 1st floor in a bedroom or spare room.

The Environmental Protection Agency recommends that your home have radon levels below 4.0 pCi/L. If your levels are above 4.0 pCi/L you can test again to confirm your test results and/or mitigate your home to lower radon levels. If you have additional questions about your results, call the Idaho Department of Health and Welfare’s Indoor Environment Program at 1-800-445-8647.

A quality radon mitigation system is able to reduce the amount of radon in your home to usually below 2 pCi/L.  Contact an experienced radon mitigation professional for more information or you may also choose to mitigate your home yourself.  There are many instructional videos on YouTube that can guide you through the process. 

Steps to reduce radon levels in your home depend on many factors. If you do it yourself, average costs for parts range from $300 to $600. The cost to have a certified radon mitigation specialist do the work in an existing home ranges from $1,500 to $2,500. Cost of installing radon-resistant features during construction runs from $300 to $500. Contact an experienced radon mitigation professional for more information.

Discuss with your builder how to incorporate radon reduction techniques into the construction of your new home.  

Yes, before you buy a house, you should have the home tested for radon.  The most common procedure for testing during a real estate transaction is for the potential buyer to request the radon test as part of the overall home inspection.  If the test is near 4.0 pCi/L, you may negotiate with the seller to have a radon mitigation system installed with the goal of bringing radon levels below 4.0 pCi/L.

No, your landlord is not legally required to test for radon. You may conduct the test yourself or ask your landlord to conduct the test.


No, your landlord is not legally required to reduce radon levels in your rental home. However, you may notify the landlord of the results and discuss with them the need for radon reduction repairs.

If you have more questions about radon, please call the Idaho Department of Health and Welfare’s Indoor Environment Program at 1-800-445-8647.

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