McClain County, OK: EPA's radon zone, explained

EPA's own radon map rates McClain County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Rank it against the rest of the country and McClain County lands in the 22nd percentile for radon potential.

Where McClain County sits nationally

McClain County, Oklahoma is home to about 48,434 people across 570.72 square miles. Population density there runs about 85 people per square mile. By population, McClain County is the 352nd largest of every county sharing its EPA zone — the 66th percentile by population within that zone. McClain County falls in EPA Radon Region 6, one of 503 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in McClain County

A Zone 3 county like McClain County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 label describes McClain County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

If McClain County tests above the action level

For a McClain 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 Oklahoma's state radon program

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

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