Is Grant County, ND a radon risk area?

EPA's own radon map rates Grant County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 67th percentile for radon potential — Grant County outranks 67% of every county EPA has rated.

Where Grant County sits nationally

About 2,247 people live in Grant County, North Dakota, spread over 1,659.233 square miles. That works out to roughly 1 people per square mile. Rank 1020 by population within its EPA zone puts Grant County at the 4th percentile among zone peers. EPA's geology-based Region 8 groups Grant County with 290 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Grant County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Some Grant County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

If Grant County tests above the action level

Nothing about Grant County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find North Dakota's state radon program

Grant County's test kit answers today; a Airthings radon monitor keeps answering for Grant County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.