Hancock County, IA radon potential

Hancock County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 76th percentile for radon potential — Hancock County outranks 76% of every county EPA has rated.

Hancock County by the numbers

Hancock County, Iowa is home to about 10,616 people across 571.005 square miles. Population density there runs about 19 people per square mile. Within its own EPA zone, Hancock County is bigger by population than 30% of the counties that share it. Hancock County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Hancock 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. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Hancock County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Hancock County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Iowa's state radon program

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

Where Hancock County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Hancock County's numbers. Whatever zone Hancock County carries, the zone explainer covers what it does and doesn't tell you about any one house.