Washington County, NE radon potential

EPA places Washington County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Washington County in the 82nd percentile nationally for radon potential — higher than 82% of the counties EPA has rated.

Where Washington County sits nationally

Washington County, Nebraska is home to about 21,254 people across 389.93 square miles. That works out to roughly 55 people per square mile. Within its own EPA zone, Washington County is bigger by population than 48% of the counties that share it. EPA's geology-based Region 7 groups Washington County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Washington County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. That doesn't mean every Washington County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

If Washington County tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Nebraska's state radon program

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

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