Benton County, IN: EPA's radon zone, explained

EPA's own radon map rates Benton County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and Benton County lands in the 74th percentile for radon potential.

Where Benton County sits nationally

Benton County, Indiana is home to about 8,853 people across 406.415 square miles. That works out to roughly 22 people per square mile. By population, Benton County is the 799th largest of every county sharing its EPA zone — the 25th percentile by population within that zone. EPA's geology-based Region 5 groups Benton County with 523 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

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. 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 Benton County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Benton County

For a Benton 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 Indiana's state radon program

For Benton County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Benton 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 Benton 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. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.