Do granite countertops emit radon? (and other radon FAQs)

Granite can contain naturally occurring radioactive elements like uranium and thorium. Some pieces of granite have more of these elements than others. These elements are radioactive and solid, but over time, they may decay into radon, says the EPA.

Granite isn't very porous and large quantities of it aren't typically used in most single-family homes, so radon isn't likely to escape in a significant enough quantity to cause an elevated radon level in a building, according to the National Radon Program Services at Kansas State University.

The danger of this amount of radon is considered low, according to VeryWellHealth.com. However, they do recommend having your entire home tested for radon if you have concerns. They point out that improving the overall air quality is more important than worrying about your countertops, adding that most radon in homes is there because it seeped in through the foundation.

The EPA says that one out of every 15 homes throughout the country, whether new or old, has elevated radon levels. Radon that originates in the soil is the main cause of radon problems because the gas makes its way up from the ground and into your home through cracks and other holes and gaps in the foundation.

All houses have some level of radon. The national average for indoor radon levels is 1.3 picocuries per liter (pCi/L), the EPA says. They recommend that all homes that test at or above 4 pCi/L install a mitigation system to help lower levels. The only way to know what level of radon your home has is by testing it.

According to the EPA, you can purchase a do-it-yourself kit by contacting your state's radon program. You may even be able to find them at a home improvement store.

Testing your granite countertops for radon is more expensive, as it requires the expertise of a qualified radon mitigation expert. Even they still may not be able to indicate the percentage of indoor radon that comes from the granite. You can find a professional by accessing the American Association of Radon Scientists and Technologists' website.

Your family's health is reason enough to test your home for radon. But you may also want to know your radon levels if you plan to sell, since most buyers will want proof of low levels or may request a test.

The EPA advises against using a radon zone map to decide whether your home should be tested. Homes with elevated radon levels can be found throughout the country, the EPA says, and all homes should be tested.

If a home contains an elevated level of radon, the cost to mitigate soil may run $1,500. The cost of treating well water is higher — about $2,000 or so — says Kansas State University National Radon Program Services. The EPA has some tips on how to find contractors to help fix your home.

Be sure your builder uses radon-resistant new construction techniques, says the EPA. This involves sealing openings, cracks and crevices in the foundation and walls. This helps prevent radon and other soil gases from entering. Installing a vent pipe from the gravel layer through the home and roof may also help keep gases out of your home.

Typically, your homeowner's policy won't cover radon inspection or mitigation. That's because homeowners' policies are typically intended to protect you from sudden, unexpected events like hail damage or vandalism, according to Pocket Sense. Radon is a gradual hazard that can be tested for and addressed, so the inspection and mitigation won't be covered.

The EPA offers an extensive list of information sources. You can also contact the Radon Hotline run by Kansas State University by calling 1-800-SOS-RADON (767-7236).