Fargo-Moorhead Radon Guide: ND & MN Rules (2026)

Updated October 22, 2026. This guide is general information, not legal or engineering advice. Rules change, so confirm with the agency listed before you start work.

Quick reference

Topic	North Dakota (Fargo, West Fargo, Horace)	Minnesota (Moorhead)
How common	63% of homes above 4.0 pCi/L; every county in EPA Zone 1 (ND DEQ)	More than 2 in 5 homes at significant risk; state average over 3 times U.S. (MDH)
When to act	EPA recommends fixing at 4.0 pCi/L or higher	MDH: mitigate at 4 pCi/L or more; consider it from 2 to 4
Who may install	Homeowner or mitigation contractor (ND DEQ)	MDH-licensed professional and company for buildings you don't own or lease (Minn. Stat. 144.4961)
Who may test others' homes	Not licensed by DEQ; DEQ lists measurement people	MDH measurement license
System label	Not described by DEQ	MDH tag next to the pressure gauge on every professional install
Home sales	Not described by DEQ	Seller disclosure for agreements signed on or after Jan. 1, 2014 (Minn. Stat. 144.496)
New homes	Not described by DEQ	Radon-resistant construction required since 2009
State contact	DEQ Radon Control Program, 701-328-5166	MDH Indoor Air Unit (see MDH radon pages)

How much radon is there in North Dakota?

ND DEQ says 63 percent of North Dakota homes have radon above the EPA's 4.0 pCi/L action level. DEQ's fact sheet notes that North Dakota is one of only two states with all of its counties in EPA Zone 1, so Cass County is in the highest-potential group. For scale, DEQ puts the average outdoor level at about 0.4 pCi/L and the national average indoor level at 1.3 pCi/L.

And in Minnesota?

MDH says more than two in five Minnesota homes have radon at levels that pose a significant health risk, and the state average is more than three times the U.S. average. MDH recommends testing every home in the state. County-level figures, including Clay County, are in the MDH radon data portal.

What's the health risk?

The EPA estimates radon causes about 21,000 lung cancer deaths a year in the United States. It is the leading cause of lung cancer among non-smokers. DEQ adds that lung cancer is the only health effect definitively tied to radon, that it typically develops 5 to 25 years after exposure, and that smokers face a higher risk.

How should I test?

The EPA and the U.S. Surgeon General recommend testing all homes below the third floor, and DEQ calls cold-weather months a great time to do it. Kits are sold at hardware and big box stores and online; DEQ suggests ones labeled EPA approved. DEQ gave away a limited number of free kits during its January 2026 radon campaign, and its radon page now says the free kits are gone. In Minnesota, testing a building you own or lease needs no license, but testing someone else's building requires an MDH measurement license.

When should I fix it, and how?

MDH recommends a mitigation system at 4 pCi/L or higher and says to consider one between 2 and 4 pCi/L. DEQ says sealing cracks, holes and sump covers can help, but those seals need ongoing upkeep, and a radon reduction system is the most effective permanent solution. DEQ lists common entry points: slab cracks, floor-wall joints, block wall pores, exposed soil in sumps, drain tile running to an open sump, and loose pipe penetrations.

Who can install a system in Fargo or West Fargo?

DEQ says a homeowner can install a system or hire an installer. DEQ publishes a list of radon mitigation and measurement people located in North Dakota. Ask any contractor for certification, references and a written proposal. Ask the contractor whether your city requires a permit for the job.

Who can install a system in Moorhead?

Minnesota's radon licensing law, Minn. Stat. 144.4961, signed in May 2015, requires an MDH license for anyone who designs or installs a mitigation system, or supervises the work on site, in a building they don't own or lease, and for companies that do mitigation. MDH requires licensees to follow ANSI/AARST standards, complete a post-mitigation checklist, attach an MDH tag next to the system's pressure gauge, give the owner an operation, maintenance and monitoring plan, and meet Department of Labor and Industry electrical rules. Owners working on their own building, and builders installing radon control in new homes before occupancy, are exempt.

What do Moorhead home sellers have to disclose?

The Minnesota Radon Awareness Act, Minn. Stat. 144.496, covers purchase agreements signed on or after January 1, 2014. Before the agreement is signed, the seller must disclose in writing any radon testing, the latest records, known levels, any mitigation and any system, along with a radon warning statement and MDH's "Radon in Real Estate Transactions." MDH notes the law does not require testing or mitigation.

What about new construction?

MDH says all new Minnesota homes have been required to be built radon-resistant since 2009: sealed openings, aggregate or a soil-gas mat and 6-mil plastic under the slab, a 3- to 4-inch vent pipe from below the slab through the roof, and an attic junction box. A fan can be added later if the house tests high.

Common questions

Is radon licensing required in Moorhead?

Yes. MDH licenses radon mitigation professionals and companies, and each professional install gets an MDH tag.

What share of North Dakota homes have high radon?

ND DEQ reports 63 percent of homes above the EPA action level of 4.0 pCi/L.

Can I still get a free radon kit in Fargo?

DEQ's radon page currently says it's out of free kits. Hardware and big box stores and online sellers carry them.

Fargo-Moorhead radon guide: North Dakota and Minnesota rules (2026)