Custer County, NE: EPA's radon zone, explained

EPA places Custer County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Custer County ranks higher in radon potential than 40% of rated counties (the 40th percentile).

How Custer County compares

Custer County, Nebraska is home to about 10,487 people across 2,575.458 square miles. That works out to roughly 4 people per square mile. By population, Custer County is the 811th largest of every county sharing its EPA zone — the 21st percentile by population within that zone. Custer County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Custer County's Zone 2 prediction lands in the gap between the two. Nothing about a Zone 2 label lowers the case for testing in Custer County — EPA recommends it in every zone, moderate included.

If Custer County tests above the action level

For a Custer 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 Nebraska's state radon program

For Custer County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Custer 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 Custer 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. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.