What EPA's radon map says about Chickasaw County

EPA places Chickasaw 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 Chickasaw County in the 77th percentile nationally for radon potential — higher than 77% of the counties EPA has rated.

How Chickasaw County compares

About 11,719 people live in Chickasaw County, Iowa, spread over 504.324 square miles. Averaged across its land area, Chickasaw County runs about 23 people per square mile. Among counties sharing Chickasaw County's EPA zone, it outranks 32% of them by population. EPA's geology-based Region 7 groups Chickasaw County with 411 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Chickasaw County

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Chickasaw County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. That doesn't mean every Chickasaw 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 Chickasaw County

Mitigation cost doesn't depend on Chickasaw 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 Iowa's state radon program

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

Chickasaw County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.