What EPA's radon map says about Benton County

Benton 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 84th percentile for radon potential — Benton County outranks 84% of every county EPA has rated.

Where Benton County sits nationally

About 25,799 people live in Benton County, Iowa, spread over 716.102 square miles. Population density there runs about 36 people per square mile. Among counties sharing Benton County's EPA zone, it outranks 52% of them by population. Benton County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Benton 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. Some Benton County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Testing and mitigation in Benton County

Mitigation cost doesn't depend on Benton 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

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

More on how this number was built

Benton County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Benton County carries, the zone explainer covers what it does and doesn't tell you about any one house.