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

EPA places Major County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Major County ranks higher in radon potential than 5% of rated counties (the 5th percentile).

How Major County compares

Major County, Oklahoma is home to about 7,569 people across 955 square miles. Averaged across its land area, Major County runs about 8 people per square mile. By population, Major County is the 888th largest of every county sharing its EPA zone — the 14th percentile by population within that zone. Geologically, Major County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Zone vs. an actual test

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Major County's Zone 3 prediction is the low end of the scale. A Zone 3 label describes Major County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

Next steps for a home in Major County

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

Where Major County's figures come from

Major County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.