Radon testing at home is inexpensive and simple: buy a short-term test kit, set it in the lowest lived-in level of your home with the windows and doors closed, then mail it to the lab. If your result is 4 pCi/L or higher, the EPA action level, do a follow-up test and plan to fix it.
This is general information, not medical advice. Talk to your doctor about your own situation.
The National Cancer Institute (NCI) describes radon as a radioactive gas released when uranium, thorium and radium break down in rocks and soil. You can't see, smell or taste it. It gets into homes through cracks in floors, walls and foundations, and it can also come from building materials or well water. Basements and first floors usually have the highest levels.
The EPA says exposure to radon is the second leading cause of lung cancer after smoking.
Scientists estimate that 15,000 to 22,000 U.S. lung cancer deaths each year are related to radon (NCI).
Radon and cigarette smoke together carry a greater risk than either one alone (NCI).
About 1 in 15 U.S. homes is estimated to have radon at or above the EPA action level of 4 picocuries per liter (pCi/L) (NCI).
The EPA says all homes should be tested for radon, and that testing is the only way to know your level of exposure. NCI notes that homes next door to each other can have different readings, so a neighbor's result tells you little about yours.
Short-term tests measure radon for a few days. The Minnesota Department of Health (MDH) says they typically run 2 to 7 days and are the place to start.
Long-term tests run 90 days or more. NCI says they give a better picture of your average level, because radon changes from day to day and season to season. MDH suggests they cover both heating and non-heating seasons.
MDH says kits are inexpensive and sold by local health departments, hardware stores, labs and other vendors. Some charge a lab fee when you mail the kit. National Radon Program Services at Kansas State University, which NCI notes is funded by the EPA, sells kits online and through its hotline at 1-800-767-7236. When this guide was written, it listed a short-term kit at $20 and a long-term kit at $30, including lab analysis.
What about plug-in digital radon monitors? MDH says they usually cost about $100 to $200 and haven't been comprehensively evaluated or approved by national radon proficiency programs. It doesn't recommend them for real estate deals or for deciding whether to install a radon system.
These tips come from MDH's testing guidance. Always follow the instructions that come with your kit, and check its expiration date.
Pick the right level. Test the lowest level of the home that's regularly used. If you spend more than 10 hours a week in the basement, test the basement.
Pick the right spot. Set the kit at least 20 inches above the floor, ideally at breathing height. Keep it 1 foot from outside walls and 3 feet from outside windows, away from drafts, heat sources like fireplaces and furnaces, and humid rooms like kitchens, bathrooms and laundry rooms.
Keep the house closed. For any test shorter than 3 months, keep windows and outside doors closed except for normal coming and going. Run your heating or air conditioning as usual.
Mind the weather. The heating season is the best time for a short-term test. If there's severe or unusually windy weather, wait.
Mail it promptly. Labs set deadlines for receiving a finished kit, so send it back as soon as the test ends.
MDH recommends two tests before deciding to install a radon mitigation system. Here is its step-by-step approach:
First short-term result 0 to 1.9 pCi/L: retest every 2 to 5 years.
2 to 7.9 pCi/L: do a long-term follow-up test.
8 pCi/L or higher: do a short-term follow-up test.
Then use the average of the two short-term tests, or the long-term result. At 4 pCi/L or higher, MDH recommends mitigation. Between 2 and 3.9 pCi/L, consider it. Below 2 pCi/L, retest every 2 to 5 years.
According to MDH, radon mitigation systems use a fan that continuously pulls air from the soil under the house and vents it outdoors through a pipe that ends above the edge of the roof. Cracks and openings in the foundation are sealed too. Common types include:
Sub-slab suction: pulls radon from beneath the foundation.
Drain tile suction: uses the existing drain tile, with covers on sump baskets.
Sub-membrane: for crawl spaces, a sealed plastic sheet covers the dirt floor and a pipe pulls soil gas from under it.
MDH says the goal is to bring radon as low as reasonably achievable, and that a quality system may bring year-round levels below 2 pCi/L. Costs generally range from $1,500 to $3,000, depending on the system and how the home was built. Get bids from qualified radon mitigation professionals. Minnesota requires them to be licensed, and your state radon program can tell you its own rules. After installation, retest to confirm the system works, waiting at least 24 hours after it starts running.
Every 2 to 5 years, even after a low result (MDH).
Before and after big changes, such as finishing a basement, adding on, replacing windows, adding insulation, installing a kitchen vent hood, or changing your heating or air conditioning system (MDH).
After a mitigation system goes in, to make sure it's working (MDH).
When buying or selling a home. MDH recommends hiring a radon measurement professional when you need an unbiased third party.
If you have lived with high radon levels, or you smoke, talk to your doctor about your lung cancer risk. NCI notes that most radon-related lung cancer deaths happen among smokers, but more than 10 percent occur among people who don't smoke.
The EPA recommends taking action to reduce radon at 4 pCi/L or higher, NCI explains. MDH suggests considering a fix between 2 and 3.9 pCi/L, and says a good system aims for a level as low as reasonably achievable.
Short-term tests usually take 2 to 7 days. Long-term tests run at least 90 days and give a better yearly average.
Yes. MDH says most radon tests can be done on your own after reading the instructions. Hire a licensed professional when you need an unbiased result, such as during a home sale.
MDH says consumer digital monitors haven't been comprehensively evaluated, and it doesn't recommend using them to decide on mitigation. Use an approved test kit or a licensed professional for that decision.
RoomMend: Safer Home Plans can't measure radon, but this iPhone and iPad app can keep the job from slipping. Log "test the basement for radon" as an issue with a timeframe, then track it, and any mitigation work that follows, through status stages with an owner, a target date and notes. It's free with an optional RoomMend Plus purchase, works offline, and is not a home inspection or safety certification.
Get RoomMend free on the App Store