What EPA's radon map says about Stephens County

EPA places Stephens 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, Stephens County ranks higher in radon potential than 21% of rated counties (the 21st percentile).

Where Stephens County sits nationally

About 44,075 people live in Stephens County, Oklahoma, spread over 870.212 square miles. That works out to roughly 51 people per square mile. Among counties sharing Stephens County's EPA zone, it outranks 63% of them by population. Stephens 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 Stephens County

Stephens County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. Even at Zone 3, Stephens County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

Next steps for a home in Stephens County

Mitigation cost doesn't depend on Stephens 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 Oklahoma's state radon program

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

More on how this number was built

Stephens 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.