Radon Testing in Madison

Updated October 2026 · 7 public sources cited

Dane County residents can pick up a $10 radon kit from the local health department, and results usually come back in two to three weeks. Here's how to test and what to do next.

Your local radon information center

Wisconsin runs regional Radon Information Centers staffed by people trained in radon measurement. For Madison, it's the Southern Wisconsin center at Public Health Madison & Dane County, which also serves Green and Rock counties.³ DHS recommends starting there, since many centers offer free or reduced-cost kits, often with lab fees included.⁴

Other places to buy a kit

DHS says kits cost $10–$30 online or at hardware stores.⁴ The county notes hardware and home stores usually sell them for under $25.¹

Does a digital monitor count?

DHS says consumer digital monitors average $100–$200, and most aren't approved by NRPP or NRSB because they can't be calibrated.⁴ They're fine for watching trends. For a mitigation decision, DHS recommends an NRPP- or NRSB-approved device or a radon contractor, and following up a high digital reading with an approved charcoal or long-term kit.⁴

When to test

Use the lowest lived-in level and keep windows and outside doors closed during a short test.⁵ Because radon swings with the seasons, a long-term test gives the truest yearly average.⁵ January is National Radon Action Month, which is when the local center pushes testing.²

What DHS says about your result

• Above 4 pCi/L: DHS says a contractor can lower it with a mitigation system.⁶
• 8 pCi/L or higher: do a second short-term test immediately. If the two average above 4, DHS recommends hiring a contractor.⁴
• Below 4: EPA still suggests considering a fix between 2 and 4, since any radon carries some risk.⁵

When to hire a tester instead

DHS says a radon measurement specialist can be useful during real estate transactions and for larger buildings like apartment complexes.⁴ Since Wisconsin doesn't license testers, look for an NRPP or NRSB "Certified Measurement Specialist."⁷

Please note: Wisconsin doesn't license radon contractors, and the state health department recommends NRPP or NRSB national certification. This page is general information summarized from public agencies, not professional advice. For advice about your home, talk with a nationally certified radon professional.