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Jan 03

How to Test Your Home for Radon

Posted on January 3, 2023 at 10:09 AM by Bridget Craker

January is Radon Action Month! Radon is a colorless, tasteless radioactive gas that comes from rocks in the soil. This gas can enter people’s homes through their basements, mainly through cracks in the foundation, dirt floors, or openings around pipes. Radon is a concern because it can lead to lung cancer, in fact, radon is the second leading cause of lung cancer in the United States, causing 21,000 lung cancer deaths per year. Smoking combined with long-term radon exposure can put people at an even higher risk for developing lung cancer. The only way to know if your home has radon is to test for it.

Radon levels vary by location; in some areas of Green County, radon levels are higher than in many areas of the state. In the 53566 zip code, which includes Monroe, 64% of homes tested for radon gas levels over the Environmental Protection Agency (EPA) recommended limit. This data is available on this interactive map from the Wisconsin Department of Health Services:

Step #1 - Get a Radon Test Kit

The first step in testing your home for radon is to get a test kit. This month, January 2023, Green County Public Health is offering FREE radon test kits to community members while supplies last. To get a test kit, please call our office at (608) 328-9390 or email us at Test kits are also available online or in some hardware stores.

Step #2 - Set Up Your Testing Device

Directions for different test kits may vary, so check the directions on your kit and follow them. In general, your first radon measurement should be made for a minimum of two days, by leaving the device in the lowest lived-in level of your home with the windows kept closed. A basement can be considered lived-in (for radon testing purposes) if it is occupied at least seven hours per week. Otherwise, the main floor is the best place to test.

Step #3 - Send the Device to a Lab

Your test kit will contain instructions about how and where to send the kit for testing. Experts are available statewide to answer any questions; get in touch with a radon expert by calling 1-888-LOW-RADON (1-888-569-7236).

Step #4 - Interpret the Results

When you receive your results, you’ll get a number indicating the radon level in your home. Radon is measured in picocuries per liter (pCi/L). Four pCi/L and over is above the Environmental Protection Agency's (EPA) recommended safe level, and action should be taken to reduce the radon level. In Wisconsin, 0.4 pCi/L is the lowest achievable level in a house and average outdoor levels, 1.8 pCi/L is the average radon level in the lowest lived-in floors of Wisconsin homes, and 4 pCi/L is the level in basements of over half of homes in some regions of the state. 

Step #5 - Retesting and Radon Mitigation

If your first 2-day radon test comes back above the action level of 4 pCi/L, then a long-term test of at least 90 days and usually around 6-12 months is recommended to gauge the home's annual radon concentration. This chart from the Wisconsin Department of Health Services clarifies the steps homeowners should take:

If your home does have radon levels over the accepted level, you can get a radon mitigation system installed to help remove radon from your home. Radon mitigation involves using a pipe and a fan to redirect radon out from underneath your home to the outside. Several certified professionals in southern Wisconsin can install a radon mitigation system in your home. The Wisconsin Department of Health Services has a list of certified contractors on their website: