Trempealeau County, WI: EPA's radon zone, explained

EPA places Trempealeau 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. Rank it against the rest of the country and Trempealeau County lands in the 51st percentile for radon potential.

Trempealeau County by the numbers

Trempealeau County, Wisconsin is home to about 30,801 people across 732.966 square miles. Population density there runs about 42 people per square mile. By population, Trempealeau County is the 479th largest of every county sharing its EPA zone — the 54th percentile by population within that zone. EPA's geology-based Region 5 groups Trempealeau County with 523 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Trempealeau County

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Trempealeau County's Zone 2 prediction lands in the gap between the two. Trempealeau County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Next steps for a home in Trempealeau County

For a Trempealeau 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 Wisconsin's state radon program

For Trempealeau County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Trempealeau 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 Trempealeau 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.