Radon rules on each side of the Wisconsin–Minnesota line
River Falls homeowners hear radon advice from both states. The rules that apply to your house are Wisconsin's, and they're much lighter than Minnesota's.
The short version
| Wisconsin | Minnesota | |
|---|---|---|
| State license for radon pros | Not required | Required since January 1, 2019 |
| Recommended credential | NRPP or NRSB certification | State license, renewed yearly |
| Tag on installed systems | Not required | State-issued tag required |
| Radon disclosure in home sales | Not required | Required |
| Radon test required to sell | No, but DHS highly recommends it | No, but disclosure of known results is required |
Your River Falls house is in Wisconsin, so Wisconsin’s rules apply to it, no matter where the contractor is based.
Wisconsin: voluntary certification
Wisconsin doesn’t require people who test for radon or install systems to be state licensed or nationally certified. The state Department of Health Services recommends choosing someone certified by one of the two EPA-recognized programs, NRPP or NRSB. Our page on finding a qualified radon professional shows how to search them.
In a Wisconsin home sale, radon testing isn’t required. DHS highly recommends it anyway.
Minnesota: licensing, tags, and disclosure
Minnesota took a stricter path. Under the Minnesota Radon Licensing Act, anyone paid to test for radon or mitigate it has needed an annual state license since January 1, 2019. Every system installed in Minnesota since then must carry a state-issued tag attached in a visible spot.
Minnesota also has a radon disclosure law for home sales. Sellers must disclose what they know about radon in the house and give the buyer a copy of the Minnesota Department of Health publication “Radon in Real Estate Transactions.”
Why this matters for a River Falls homeowner
Two practical takeaways.
First, a contractor who works on both sides of the line may be used to Minnesota’s standards, which is a point in their favor. Just don’t assume a Wisconsin job gets the same paperwork. Ask what documentation you’ll receive: the pressure gauge reading at install, a post-mitigation test, and a label on the pipe.
Second, if you’re house hunting on both sides of the St. Croix, the sale process differs. A Minnesota seller has to put radon on paper. A Wisconsin seller doesn’t, so the burden to ask and test is on you.
Every state draws its own line
It isn’t just Wisconsin and Minnesota. Pennsylvania, for example, requires radon testers and mitigators to be certified by its Department of Environmental Protection, so a buyer there checks a state list instead of a national one. If you’re reading online advice about radon mitigation in York, PA or anywhere else, check which state’s rules it’s based on before you apply it to a house in River Falls.
Back to the River Falls radon guide.
Border questions
Can a Minnesota-licensed contractor work on my Wisconsin house?
Yes. Wisconsin doesn't require a state radon license, so there's nothing extra they need to work here. Ask whether the person doing the work also holds NRPP or NRSB certification, which Wisconsin DHS recommends.
Will my Wisconsin system get a Minnesota tag?
No. Minnesota's tag requirement covers systems installed in Minnesota. A Wisconsin system should still be labeled and have a working pressure gauge.
I'm buying in Hudson but also looking in Stillwater. What changes?
In Minnesota, the seller has to give you radon disclosures and an MDH publication. In Wisconsin, no radon disclosure or test is required, so ask for any past results and test during your inspection.
- We don't sell tests or install systems
- Every figure links to its source
- Covers Wisconsin and Minnesota rules