What EPA's radon map says about Clay County

Clay County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Clay County in the 72nd percentile nationally for radon potential — higher than 72% of the counties EPA has rated.

How Clay County compares

About 6,103 people live in Clay County, Nebraska, spread over 572.289 square miles. Averaged across its land area, Clay County runs about 11 people per square mile. Among counties sharing Clay County's EPA zone, it outranks 18% of them by population. Geologically, Clay County is grouped into EPA Region 7 alongside 411 other counties that share its rock and soil setting.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Clay County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. Being in Zone 1 raises the odds Clay 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.

Next steps for a home in Clay County

Mitigation cost doesn't depend on Clay County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Nebraska's state radon program

Clay County's test kit answers today; a Airthings radon monitor keeps answering for Clay 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

Clay 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.