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

Phelps 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 75th percentile for radon potential — Phelps County outranks 75% of every county EPA has rated.

Where Phelps County sits nationally

Phelps County, Nebraska is home to about 9,042 people across 539.765 square miles. That works out to roughly 17 people per square mile. By population, Phelps County is the 795th largest of every county sharing its EPA zone — the 25th percentile by population within that zone. EPA's geology-based Region 7 groups Phelps 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 — Phelps County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. 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 Phelps County specifically.

If Phelps County tests above the action level

For a Phelps 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 Phelps County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Phelps 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 Phelps County's figures come from

Phelps County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.