What EPA's radon map says about Monroe County

EPA places Monroe 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, Monroe County ranks higher in radon potential than 55% of rated counties (the 55th percentile).

How Monroe County compares

About 46,370 people live in Monroe County, Wisconsin, spread over 900.904 square miles. Averaged across its land area, Monroe County runs about 51 people per square mile. Among counties sharing Monroe County's EPA zone, it outranks 66% of them by population. Geologically, Monroe County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Zone vs. an actual test

EPA's Zone 2 rating for Monroe County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Monroe County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Monroe County

Mitigation cost doesn't depend on Monroe 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 Wisconsin's state radon program

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

More on how this number was built

Monroe 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.