Is Dickinson County, IA a radon risk area?
EPA places Dickinson 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 81st percentile for radon potential — Dickinson County outranks 81% of every county EPA has rated.
Dickinson County by the numbers
About 18,158 people live in Dickinson County, Iowa, spread over 380.532 square miles. Population density there runs about 48 people per square mile. Rank 597 by population within its EPA zone puts Dickinson County at the 44th percentile among zone peers. Dickinson 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
Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Dickinson County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. That doesn't mean every Dickinson 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.
If Dickinson County tests above the action level
Nothing about Dickinson 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
Dickinson County's test kit answers today; a Airthings radon monitor keeps answering for Dickinson 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
Dickinson County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Dickinson County carries, the zone explainer covers what it does and doesn't tell you about any one house.