What EPA's radon map says about Colfax County

Colfax County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 76th percentile for radon potential — Colfax County outranks 76% of every county EPA has rated.

Where Colfax County sits nationally

About 10,826 people live in Colfax County, Nebraska, spread over 411.46 square miles. That works out to roughly 26 people per square mile. Among counties sharing Colfax County's EPA zone, it outranks 30% of them by population. Colfax County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

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 — Colfax County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Colfax County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Colfax County

Mitigation cost doesn't depend on Colfax County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Nebraska's state radon program

Colfax County's test kit answers today; a Airthings radon monitor keeps answering for Colfax County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

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