Thomas County, NE: EPA's radon zone, explained

EPA places Thomas County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Thomas County ranks higher in radon potential than 0% of rated counties (the 0th percentile).

How Thomas County compares

Thomas County, Nebraska is home to about 634 people across 712.554 square miles. That works out to roughly 1 people per square mile. By population, Thomas County is the 1020th largest of every county sharing its EPA zone — the 1st percentile by population within that zone. EPA's geology-based Region 7 groups Thomas County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Thomas County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. A Zone 3 rating means Thomas County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

Testing and mitigation in Thomas County

For a Thomas 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 Nebraska's state radon program

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

Where Thomas County's figures come from

Thomas County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.