Not legal advice. This summary is based on information from the North Dakota DEQ and the Minnesota Department of Health. Rules can change; for a specific sale or building project, check with your agent, attorney or building official.
Side by side
| North Dakota (Fargo, West Fargo, Horace, Casselton) | Minnesota (Moorhead, Dilworth) | |
|---|---|---|
| Who can mitigate | No state license. The DEQ recommends nationally certified pros (NRPP or NRSB). | MDH-licensed radon mitigation professionals and companies only. |
| System labeling | Industry standard labeling; no state tag. | Systems receive an MDH system tag. |
| Home sales | No radon-specific disclosure law like Minnesota's. Ask your agent what the standard disclosure forms cover. | Radon Awareness Act (since 2014): sellers disclose known radon tests, results and systems, and give buyers MDH radon information. |
| New homes | Depends on the codes adopted locally. Ask your builder. | State building code has required passive radon features in new homes since 2009. |
| Radon zone | All counties, including Cass, are EPA Zone 1. | Clay County is EPA Zone 1. |
Buying or selling in North Dakota
North Dakota law doesn't require a radon test or mitigation for a sale. Buyers commonly add a radon test to the inspection contingency. If the result is 4 pCi/L or higher, the usual outcomes are a seller-installed system with a post-mitigation test, a credit at closing, or a price adjustment. Sellers who already know about high radon should talk with their agent about disclosure, since general duties to disclose known material problems can still apply.
Buying or selling in Minnesota
Under the Radon Awareness Act, a Minnesota seller must disclose in writing whether the home has been tested, the results, and whether there's a mitigation system, along with details of the system. The seller also provides MDH's radon publication. Testing and mitigation are still negotiated between the parties.
Building a new home
In Minnesota, new homes must include passive radon control features, and adding a fan later (making it an active system) has its own code requirements and inspection. In North Dakota, ask your builder whether radon-resistant features are included; the EPA's recommended features are a gravel layer, a sealed vapor barrier, sealed openings, and a vent pipe. In either state, test after you move in.
Landlords and tenants
We're not aware of a general requirement in either state for landlords to test rental homes for radon; if you own rentals, check with the DEQ or MDH. Testing and fixing high levels is good practice and protects tenants who sleep in basement rooms.
Where to check
- North Dakota DEQ radon program: testing information and a list of certified contractors.
- Minnesota Department of Health radon program: license lookup, real estate rules, and the passive-system code.
- EPA: health information and the Citizen's Guide to Radon.
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Common questions
I live in Fargo. Do Minnesota rules apply to me?
No. North Dakota homes follow North Dakota rules. Minnesota rules apply to homes in Moorhead, Dilworth and the rest of Minnesota.
Does a Minnesota seller have to install a radon system?
No. The Radon Awareness Act is about disclosure and information. Whether to test or mitigate is negotiated between buyer and seller.
Where is the ND DEQ list of radon contractors?
The ND DEQ radon program publishes a list of contractors on its website. Check the certifying body (NRPP or NRSB) for current status too.