Douglas County, KS radon potential

EPA places Douglas 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. Nationally, Douglas County ranks higher in radon potential than 95% of rated counties (the 95th percentile).

How Douglas County compares

Douglas County, Kansas is home to about 121,989 people across 455.765 square miles. Population density there runs about 268 people per square mile. Within its own EPA zone, Douglas County is bigger by population than 85% of the counties that share it. EPA's geology-based Region 7 groups Douglas County with 411 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Douglas County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. Being in Zone 1 raises the odds Douglas County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

If Douglas County tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Kansas's state radon program

For Douglas County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Douglas 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 Douglas 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. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.