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

EPA's own radon map rates Wells County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Wells County ranks higher in radon potential than 69% of rated counties (the 69th percentile).

How Wells County compares

Wells County, North Dakota is home to about 3,803 people across 1,270.535 square miles. Population density there runs about 3 people per square mile. By population, Wells County is the 959th largest of every county sharing its EPA zone — the 10th percentile by population within that zone. EPA's geology-based Region 8 groups Wells County with 290 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Wells County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. Some Wells 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 Wells County tests above the action level

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

The methodology guide shows exactly which EPA and Census sources feed Wells County's numbers. Whatever zone Wells County carries, the zone explainer covers what it does and doesn't tell you about any one house.