Radon in Clay County, MN: Moorhead Testing and Costs

Minnesota is one of the most radon-prone states on EPA's map, and Clay County is part of that pattern. EPA's 1993 Map of Radon Zones puts 68 of Minnesota's 87 counties in Zone 1, including Clay, meaning a predicted county average indoor screening level above 4 pCi/L.

The Census Bureau relationship file maps 13 ZIP areas to Clay County, all in Zone 1 counties; 4 of them cross into a neighboring county. Across the Red River, Cass County, North Dakota is in a different state program, so Fargo-Moorhead homeowners on the Minnesota side follow Minnesota rules.

HomeGuide's Feb 2026 survey prices a sub-slab system at $1,200 to $2,000 installed. Minnesota adds a state system tag that a licensed mitigator attaches to every system, at $75 per tag under the state fee schedule (MDH).

Licensing and permits

Annual state license: since January 1, 2019, anyone paid to test for or mitigate radon in Minnesota must hold an annual Minnesota Department of Health license (Minn. Stat. § 144.4961). A mitigation professional license is $250 a year, and a mitigation company license $100 a year, waived for a one-professional company (MDH fee schedule).

System tag: every radon mitigation system installed in Minnesota on or after January 1, 2019 must carry an MDH system tag attached by the licensed professional (Minn. Stat. § 144.4961, subd. 4). Look for it on the pipe.

Homeowner exception: MDH says installing a system in a building you own or lease does not require a license, but the professional rules apply to anyone you hire.

Local permits: Moorhead and the county's smaller cities set building permit rules; HomeGuide puts radon permits at $25 to $150 where required.

Local conditions

Western Clay County lies on the floor of glacial Lake Agassiz, the Red River Valley, where thick lake clays and silts were laid down as the ice melted. To the east, sandy beach ridges and glacial till rise toward Hawley and Ulen. Clay soils crack as they dry, opening paths for soil gas, while sandy ridges let it move freely.

Most homes in Moorhead, Dilworth and the county's towns have full basements, which EPA's Consumer's Guide treats as the standard case for sub-slab suction.

Long, cold winters keep houses closed for months and the stack effect strongest, conditions under which indoor radon tends to read highest; EPA's test guidance calls for closed-house conditions.

Spring flooding on the Red River is a local fact of life, and many Moorhead basements have sump pits and drain tile installed for water. Those same pits make a natural place to apply suction, as long as the sump lid is sealed.

What drives local prices

Full basements on lake clay usually take one or two suction points; HomeGuide's published sub-slab range is $1,200 to $2,000, and extra points are est. $250 to $500 each in our calculator.
State costs built into bids: the $75 MDH system tag and licensing fees under Minn. Stat. § 144.4961 are part of a licensed installer's overhead.
Wet basements with drain tile can use drain-tile suction, $900 to $1,800 (HomeGuide).
Permit $25 to $150 and professional retest $125 to $400 (HomeGuide).
Freeze protection: exterior fans and condensate in winter are design details a local installer should address (our observation).

Common jobs

Sub-slab systems in Moorhead and Dilworth basement homes.
Drain-tile suction where basements already have perimeter drains.
Systems in newer subdivisions on the city's south side.
Pre-sale tests and tags for Minnesota-side closings.

From test to fixed, and where we cover

Step 1: test in the heating season with the house closed. Step 2: at 4 pCi/L or more, get two bids from MDH-licensed mitigation professionals.

Step 3: compare them with the calculator. Step 4: retest after installation and confirm the MDH tag is on the system.

We cover Moorhead, Dilworth, Barnesville, Hawley, Glyndon, Ulen, Sabin and Felton, along I-94, US 10 and US 75.

Communities: Moorhead, Dilworth, Barnesville, Hawley, Glyndon, Ulen, Sabin, Felton

Before you sign

Radon is a long-term exposure risk (EPA Citizen's Guide); schedule a fix after comparing two licensed bids, and confirm the MDH tag is installed.

Questions about Clay County

Is radon high in Moorhead?

EPA rates Clay County Zone 1, a predicted average above 4 pCi/L. Test your own home to know its level.

Does Minnesota license radon mitigators?

Yes. MDH issues annual licenses under Minn. Stat. § 144.4961, and every system needs an MDH tag.

What does the Minnesota radon tag cost?

MDH's fee schedule sets it at $75 per tag, attached by the licensed professional.

What does mitigation cost in Clay County?

HomeGuide's national range for a sub-slab system is $1,200 to $2,000.

Sources

Rules and fees change; confirm with the state radon office. Price your own system with the radon mitigation cost calculator, read the radon mitigation cost guide, or check any ZIP with the radon levels by ZIP tool.