Is Henry County, IA a radon risk area?

EPA places Henry County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Henry County in the 81st percentile nationally for radon potential — higher than 81% of the counties EPA has rated.

How Henry County compares

About 19,361 people live in Henry County, Iowa, spread over 434.288 square miles. Averaged across its land area, Henry County runs about 45 people per square mile. Rank 587 by population within its EPA zone puts Henry County at the 45th percentile among zone peers. EPA's geology-based Region 7 groups Henry County with 411 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Henry County

Where the national indoor average runs about 1.3 pCi/L, Henry County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. That doesn't mean every Henry County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

Next steps for a home in Henry County

Nothing about Henry 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 Iowa's state radon program

Henry County's test kit answers today; a Airthings radon monitor keeps answering for Henry County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 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. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.