Radon and Wisconsin real estate: what buyers and sellers should know

What Wisconsin requires, and what it doesn’t

Radon testing isn’t required for real estate transactions in Wisconsin. DHS still highly recommends it, and it publishes a home buyers and sellers brochure that covers the basics. Many buyers include a radon test in their inspection, so sellers should expect the question.

If you’re buying

• Ask whether the house has been tested. Get the date, the result, and who ran it. An old homeowner kit result is a starting point, not an answer.
• Test during your inspection period. A short-term test with a continuous monitor fits most inspection windows. Place it on the lowest floor you’d actually use, under closed-house conditions.
• If there’s a system, check it. Look for the manometer on the pipe, a fan outside the living space, and a discharge above the roof. Ask for the post-mitigation test.
• If the number is high, talk with your agent about how to handle it in the deal. A certified mitigator can give an estimate quickly.

If you’re selling

• Test before you list if you haven’t recently. It’s better to know your number before a buyer’s inspector tells you.
• Keep your paperwork. Past test results, the install date of any system, and the post-mitigation test all help a buyer trust the house.
• Don’t disturb a test in progress. Opening windows or running fans during a buyer’s test can void the result and slow the deal.

Timing matters in Wisconsin

Radon levels tend to run higher when a house is closed up for the heating season. A sale that closes in July may test differently than the same house would in January. That doesn’t make a summer result wrong. It just means a low summer number is worth confirming later with a long-term test.

For how the tests work, see our radon testing guide. To find a certified measurement specialist, see how to search NRPP and NRSB. Or go back to the Wisconsin radon guide.