Morrow County, OH: EPA's radon zone, explained

EPA places Morrow 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. Morrow County sits at the 87th percentile nationally for radon potential — above 87 of every 100 rated counties.

Morrow County by the numbers

Morrow County, Ohio is home to about 35,927 people across 406.134 square miles. That works out to roughly 88 people per square mile. By population, Morrow County is the 416th largest of every county sharing its EPA zone — the 61st percentile by population within that zone. Geologically, Morrow County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Morrow County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. 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 Morrow County specifically.

Next steps for a home in Morrow County

For a Morrow 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 Ohio's state radon program

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

Where Morrow 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. Whatever zone Morrow County carries, the zone explainer covers what it does and doesn't tell you about any one house.