Although the Environmental Protection Agency (EPA) does not have a regulation specifying how long a radon test result remains acceptable to use, they do recommend testing every two years. So a radon test more than two years old may not be accurate. Conditions in the soil under the home can change and the floor slab can develop new cracks that allow more soil gases into the home. So a radon test more than two years old may not be acceptable to a homebuyer, based on the EPA guidelines. 

    Incidentally, retesting is also recommended every two years for homes with an active radon mitigation system installed and functioning for the same reasons, and because the efficiency of the mitigation system may deteriorate over time. 

     For more information about radon we recommend that you visit the U.S. Environmental Protection Agency’s radon homepage at http://www.epa.gov/radon/. Click on any of the two report covers below to download consumer guides to radon from the EPA.  

    Also, see our blog posts How can not testing for radon be an expensive mistake for homebuyers? and Can a homebuyer do their own radon test for a real estate transaction with a self-test kit?

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Here’s links to a collection of our blog posts about “RADON":

• Is a radon mitigation fan required to be on a dedicated circuit breaker/fuse in the electric panel?

• What happens to a radon test result if the windows were opened, the test device moved, or there was any other evidence of tampering during the test? 

• Where do I find the Florida laws regarding radon?

• Can I test vacant land for radon before building a house? 

• Is radon mitigation possible for a condominium?

• Do radon mitigation systems require maintenance?

• What is the average life expectancy of a radon mitigation system?  

• Do older houses have higher radon levels than new houses? 

• Can the seller tamper with a homebuyer's radon test to change the results?

• How long does it take to get the results of a radon test? 

• Will opening the windows reduce the radon level in a house?

• How was it determined that between 15,000 and 22,000 lung cancer deaths each year are caused by radon?

• What is the danger of radon in well water?

• What are the symptoms of radon poisoning? 

• Does Florida have radon?

• Where does radon come from? 

• Should homeowners get a pre-listing radon test before selling their home?

• What are a homebuyer's options when the radon test comes back high (4.0 pico-curies/liter or more)? 

• Do granite countertops emit radon?

• How can I tell if a house has a radon mitigation system? 

• Can a mobile/manufactured home have a high radon problem?

• Do I need to test for radon when buying a condominium? 

• What does a radon mitigation contractor do to lower the radon level in a home?

• Will the radon test come back sky-high in a house that has been empty and closed-up for months? 

• What is radon? Should I be concerned about it?

• Should I buy a house with a high radon level? 

• What is the average radon level of indoor and outdoor air in America?

• What is the operating cost of a radon mitigation system? 

• Should I buy a house with a radon mitigation system?

• Does the buyer or seller of a home pay for radon mitigation when the radon test comes back high? 

• What is the probability of having high radon in a Florida house?

• How quickly do I need to reduce a high radon level in my house? 

• Does a home inspector check for radon?

• What are the problems with underground return air ducts? 

• What is the probability of having high radon in a Florida house?

• What factors can change radon test levels up or down?

    Visit our RADON page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.