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

EPA's own radon map rates Stark County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Stark County sits at the 86th percentile nationally for radon potential — above 86 of every 100 rated counties.

Where Stark County sits nationally

Stark County, North Dakota is home to about 33,767 people across 1,334.914 square miles. That works out to roughly 25 people per square mile. By population, Stark County is the 436th largest of every county sharing its EPA zone — the 59th percentile by population within that zone. EPA's geology-based Region 8 groups Stark County with 290 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Stark County

Stark 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. Being in Zone 1 raises the odds Stark 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 Stark County

For a Stark 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 Stark County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Stark 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 Stark County's figures come from

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.