How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manufactured and modular homes

Does Florida have radon?

Thursday, July 12, 2018

Radon is a radioactive gas that is produced by radium deposits, which are in the soil everywhere on earth, usually in a small amount. So a little radon gas is in the air we breathe every day. Most of Florida has minor amounts of radium in the soil and, consequently, low radon levels.

    But a few parts in the state, including our own Alachua and Marion counties, have places with higher radium deposits and corresponding higher radon levels. Because radon causes lung damage that can lead to cancer, a high radon level inside your home can increase your risk of lung cancer. It is named by the CDC as the second-leading cause of lung cancer, behind cigarettes.

    The maps show Alachua and Marion, along with an overall map of the state. Color-coded areas indicate where there is a higher likelihood of elevated radon (red), medium (yellow), and low chance (green). The map was prepared by the Florida Department of Health, which interprets the colors slightly differently: red indicates areas where active radon controls are recommended, yellow means passive radon control is advised, and green means that no radon control system is generally necessary. Alachua has a much larger red area, which basically runs north-south along I-75, and east-west along Newberry Road and University Avenue.

    As you can see, the red and yellow zones are small in relation to the size of the state. A radon map is available for downloading at the Florida Department of Health website at for each of the following counties: Alachua, Brevard, Charlotte, De Soto, Gadsden, Hardee, Highlands, Hillsborough, Indian River, Leon, Manatee, Marion, Osceola, Polk, Putnam, Sarasota, and Seminole.

    The Department of Health also maintains a database of the percentage of homes in each zip code in Florida that have had their indoor radon level tested and the results reached or exceeded the 4.0 pico-curies per liter of air level at which active controls (mitigation) is recommended. You can check your zip code at

    Some zip codes have not had enough tests to provide statistical accuracy of the percentage results. Also, it’s important to note that both the radon maps and zip code percentages only tell you the odds of whether your particular home may have an elevated indoor radon level. The only way to be sure is to test.

    Also, see our blog posts How can not testing for radon be an expensive mistake for homebuyers? and What are the symptoms of radon poisoning? and Should homeowners get a pre-listing radon test before selling their home?

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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?

Where does radon come from? 

For how many years does an old radon test result remain valid?

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?

How can not testing for radon be an expensive mistake for homebuyers? 

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.

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