Sedgwick County, CO: EPA's radon zone, explained

Sedgwick County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, Sedgwick County ranks higher in radon potential than 67% of rated counties (the 67th percentile).

How Sedgwick County compares

Sedgwick County, Colorado is home to about 2,257 people across 548.041 square miles. That works out to roughly 4 people per square mile. By population, Sedgwick County is the 1019th largest of every county sharing its EPA zone — the 4th percentile by population within that zone. Sedgwick County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Sedgwick County

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Sedgwick County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. Some Sedgwick County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Testing and mitigation in Sedgwick County

For a Sedgwick 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 Colorado's state radon program

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

Where Sedgwick County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Sedgwick County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.