Is Grant County, OK a radon risk area?

EPA's own radon map rates Grant County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally, Grant County ranks higher in radon potential than 2% of rated counties (the 2nd percentile).

Where Grant County sits nationally

About 4,123 people live in Grant County, Oklahoma, spread over 1,000.74 square miles. Averaged across its land area, Grant County runs about 4 people per square mile. Rank 960 by population within its EPA zone puts Grant County at the 7th percentile among zone peers. EPA's geology-based Region 6 groups Grant County with 502 other counties nationally sharing its underlying rock and soil profile.

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, Grant County's Zone 3 prediction is the low end of the scale. Even at Zone 3, Grant 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 Grant County

Nothing about Grant County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Oklahoma's state radon program

Grant County's test kit answers today; a Airthings radon monitor keeps answering for Grant 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

Grant 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.