Is Floyd County, IA a radon risk area?

EPA places Floyd 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. Nationally that's the 79th percentile for radon potential — Floyd County outranks 79% of every county EPA has rated.

How Floyd County compares

About 15,008 people live in Floyd County, Iowa, spread over 500.571 square miles. That works out to roughly 30 people per square mile. Rank 661 by population within its EPA zone puts Floyd County at the 38th percentile among zone peers. Floyd County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Floyd County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. That doesn't mean every Floyd 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.

Testing and mitigation in Floyd County

Nothing about Floyd 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

Floyd County's test kit answers today; a Airthings radon monitor keeps answering for Floyd County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

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. Whatever zone Floyd County carries, the zone explainer covers what it does and doesn't tell you about any one house.