Dunn County, ND: EPA's radon zone, explained

EPA's own radon map rates Dunn County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Dunn County ranks higher in radon potential than 70% of rated counties (the 70th percentile).

How Dunn County compares

Dunn County, North Dakota is home to about 4,031 people across 2,008.492 square miles. Averaged across its land area, Dunn County runs about 2 people per square mile. By population, Dunn County is the 951st largest of every county sharing its EPA zone — the 11th percentile by population within that zone. Dunn County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Dunn County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Being in Zone 1 raises the odds Dunn County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Testing and mitigation in Dunn County

For a Dunn County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find North Dakota's state radon program

For Dunn County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Dunn County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Dunn County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Dunn County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.