Black Hawk County, IA: EPA's radon zone, explained

Black Hawk 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 Black Hawk County in the 95th percentile nationally for radon potential — higher than 95% of the counties EPA has rated.

How Black Hawk County compares

Black Hawk County, Iowa is home to about 132,348 people across 565.773 square miles. Population density there runs about 234 people per square mile. By population, Black Hawk County is the 151st largest of every county sharing its EPA zone — the 86th percentile by population within that zone. Black Hawk County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Black Hawk County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Black Hawk County specifically.

Next steps for a home in Black Hawk County

For a Black Hawk County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Iowa's state radon program

For Black Hawk County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Black Hawk County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

Where Black Hawk County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.