Douglas County, NV: EPA's radon zone, explained

EPA's own radon map rates Douglas County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Douglas County in the 90th percentile nationally for radon potential — higher than 90% of the counties EPA has rated.

How Douglas County compares

Douglas County, Nevada is home to about 49,564 people across 710.537 square miles. That works out to roughly 70 people per square mile. By population, Douglas County is the 314th largest of every county sharing its EPA zone — the 71st percentile by population within that zone. EPA's geology-based Region 9 groups Douglas County with 94 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Douglas County

Douglas County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Douglas County specifically.

Next steps for a home in Douglas County

For a Douglas 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 Nevada'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

The methodology guide shows exactly which EPA and Census sources feed Douglas County's numbers. Whatever zone Douglas County carries, the zone explainer covers what it does and doesn't tell you about any one house.