Get a Test Kit
- Public Health Madison & Dane County sells test kits for $10, cash or check only.(PHMDC) Pick one up weekdays at the Atrium, 2300 S. Park St., Suite 2010, or the East Washington office, 2705 E. Washington Ave., 2nd floor.(PHMDC) Questions: 608-243-0392.
- By mail: send a check made out to the Madison City Treasurer to PHMDC, Attn: Radon Program, 2300 S. Park Street, Room 2022, Madison, WI 53713. Results usually come back two to three weeks after you mail the kit to the lab.(PHMDC)
- Hardware and home stores also sell kits, usually for under $25.(PHMDC) Kits from stores or online can run about $30 once a separate lab fee is added.(Wisconsin DHS)
- The office is part of Wisconsin's network of Radon Information Centers, which also serves Green and Rock counties.(Wisconsin DHS) Statewide help line: 1-888-569-7236 (1-888-LOW-RADON).(Wisconsin DHS)
Why It Matters
- Radon is a radioactive gas you can't see, smell or taste. It comes from uranium breaking down in nearly all soils, and it gets into houses through cracks and gaps in the foundation.(EPA)
- EPA estimates about 21,000 lung cancer deaths a year in the U.S. from radon, about 2,900 of them in people who never smoked. It's the leading cause of lung cancer in non-smokers.(EPA) Smoking and radon together raise the risk far more than either alone.(EPA)
- Dane County is in Zone 1, EPA's highest radon potential, but EPA says the map shouldn't decide whether you test: every home should be tested.(EPA)
- Public Health Madison & Dane County says about half of the Dane County homes tested in recent years had high radon.(PHMDC) Statewide, DHS says about 1 in 10 homes has high levels,(Wisconsin DHS) and elevated levels have been found in every county.(Governor's proclamation) DHS publishes a map of test results by county and ZIP code.(Wisconsin DHS)
- Any home can have high radon: new or old, drafty or tight, with or without a basement. Neighbors' homes can test very differently, so their result doesn't tell you yours.(National Cancer Institute)
How to Test
Radon is measured in picocuries per liter (pCi/L). EPA says to fix your home at 4 pCi/L or higher, and to consider fixing between 2 and 4, since no level is known to be safe.(EPA) The average U.S. home is about 1.3 pCi/L; outdoor air is about 0.4.(EPA)
- Short-term tests stay in place 2 to 90 days; long-term tests more than 90 days and give a better picture of the year-round average.(EPA)
- Where: the lowest level you use regularly, in a room you're in often, not a kitchen or bathroom. Set the kit at least 20 inches off the floor, away from drafts, heat, humidity and outside walls.(EPA)
- Closed house: for a 2- to 3-day test, close windows and outside doors 12 hours before you start and keep them closed except for normal coming and going. Skip severe storms and high winds.(EPA)
- When you're done, reseal the kit and mail it to the lab right away.(EPA)
- Take a short-term test. If it's 4 pCi/L or higher, test again.
- Follow up with a long-term test, or a second short-term test if you need an answer soon. If the first result was over 8, do the second short-term test right away.
- Fix the home if the long-term result is 4 or higher, or if the two short-term tests average 4 or higher.(EPA)
Retest every two to five years, and after foundation work, heating or cooling changes, or new windows and doors.(Wisconsin DHS) Public Health Madison & Dane County says every two years.(PHMDC) Test before you finish a basement, and again if you start using a lower level.(EPA)
Fixing a High Level
- How it works: the usual fix, sub-slab suction, is a pipe through the basement floor with a fan that pulls radon from under the house and vents it above the roof. EPA calls it the most common and usually the most reliable method.(EPA) Public Health Madison & Dane County says a system can cut radon by up to 99%.(PHMDC)
- Sump pits can be capped and used as the suction point. Crawlspaces get heavy plastic over the dirt with suction underneath.(EPA)
- Sealing cracks alone isn't enough, and opening windows only works while they're open; levels come back within about 12 hours of closing up.(EPA)
- Cost: Wisconsin DHS puts a typical system at $1,000 to $2,000, depending on the home's size and design.(Wisconsin DHS) EPA says most homes can be fixed for about the cost of other common home repairs; get estimates.(EPA) No Wisconsin rebate or grant for mitigation was found.
- Living with a system: the fan runs all the time; don't turn it off. A gauge on the pipe, usually a U-shaped manometer, shows it's working; check it regularly. Fans can last five years or more, and the system adds a little to your electric bill.(EPA)
- Retest within 30 days of installation, but no sooner than 24 hours after the fan starts. EPA recommends an independent test rather than relying only on the installer's.(EPA)
Hiring a Mitigation Contractor
- Wisconsin doesn't license radon testers or mitigators. DHS recommends someone certified by NRPP or NRSB, the two national programs EPA recognizes.(Wisconsin DHS) DHS keeps no contractor list; use the NRPP or NRSB "find a professional" search by ZIP code.(Wisconsin DHS)
- Ask for proof of certification and insurance, diagnostic testing, a warning device, a post-installation test, and in writing any guarantee to get below 4 pCi/L, and for how long.(EPA)
- The current standard for fixing existing homes is ANSI/AARST SGM-SF-2023.(EPA) A do-it-yourself system done without the right knowledge can raise radon levels.(EPA)
Buying or Selling a Home
- Wisconsin doesn't require a radon test to sell a home; DHS strongly recommends one.(Wisconsin DHS)
- The state's real estate condition report asks sellers whether they're aware of a radon defect. "Aware" means the owner has notice or knowledge of it.(Wis. Stat. 709.03)
- Wisconsin's standard residential offer to purchase (WB-11) has a radon testing contingency buyers can include. Under it, the buyer has 20 days by default to deliver a result of 4.0 pCi/L or more with a written objection, and the seller may cure by installing a mitigation system and showing a follow-up test under 4.0.(WB-11 offer form)
- For a sale, test the lowest level a buyer could use regularly, finished or not, with steps to prevent or detect tampering.(EPA) DHS says consumer digital monitors aren't for real estate tests.(Wisconsin DHS)
New Homes and Remodels
- Wisconsin's building code doesn't require radon-resistant construction in new homes,(Wis. Admin. Code SPS 321) and a 2019 bill to require it failed.(2019 SB 875) DHS's 2026 goals include moving toward it.(Wisconsin DHS)
- Radon-resistant features: a gravel layer under the slab, plastic sheeting over it, sealed cracks and openings, a vent pipe through the roof, and an attic outlet for a fan if one is needed later.(EPA) EPA says building them in costs less than fixing a house later.(EPA)
- Test every new home after you move in, even one built radon-resistant.(EPA) Finishing a basement? Test first; radon-resistant steps are cheaper to add during the work.(EPA) See the remodel permit guide for permit rules by town.
- Licensed child care centers in Wisconsin must test for radon and fix high levels within 12 months. Schools aren't required to test.(Wisconsin DHS)
Private Wells
- Every Wisconsin well has some radon. The highest levels are in north-central and northwestern Wisconsin, where groundwater runs through granite.(Wisconsin DNR) In a survey of more than 500 wells, none south of a line from La Crosse to Green Bay, which includes Dane County, was over 5,000 pCi/L.(Wisconsin DHS)
- Most of the risk comes from breathing radon released by showers and laundry. Test the air first; if it's over 4 pCi/L and you have a well, test the water too. DNR suggests considering treatment above 4,000 pCi/L in water.(Wisconsin DNR)
- Whole-house treatment uses aeration or activated carbon. A tap filter doesn't help with radon released into the air.(EPA)
Questions
Where can I get a radon test kit in Dane County?
Public Health Madison & Dane County sells kits for $10, cash or check, at 2300 S. Park St. (Suite 2010) and 2705 E. Washington Ave. (2nd floor), Madison. Call 608-243-0392 with questions. Hardware and home stores also sell kits, usually for under $25.
Is radon a problem in Dane County?
Dane County is in EPA's highest radon zone, Zone 1. Public Health Madison & Dane County says about half of the county's homes tested in recent years had high radon, and elevated levels have been found in every Wisconsin county. The only way to know about your home is to test it.
What radon level is safe?
EPA says to fix your home at 4 pCi/L or higher and to consider fixing between 2 and 4, because no level is known to be safe. The average U.S. home is about 1.3 pCi/L.
How much does radon mitigation cost in Wisconsin?
Wisconsin's Department of Health Services puts a typical mitigation system at $1,000 to $2,000, depending on the home's size and design. Get more than one estimate from certified contractors.
Does Wisconsin license radon contractors?
No. Wisconsin DHS recommends hiring someone certified by one of the two national programs EPA recognizes, NRPP or NRSB, and points to their online directories.
Do I have to test for radon to sell my house in Wisconsin?
No. The state condition report asks whether you're aware of a radon defect, and Wisconsin's standard offer to purchase includes a radon testing contingency buyers can use. DHS strongly recommends testing.
Does my new house have radon protection?
Not necessarily. Wisconsin's building code doesn't require radon-resistant construction in new homes. EPA says to test every new home after you move in.