What EPA's radon map says about Sauk County

Sauk County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Nationally, Sauk County ranks higher in radon potential than 57% of rated counties (the 57th percentile).

How Sauk County compares

About 66,486 people live in Sauk County, Wisconsin, spread over 831.587 square miles. Population density there runs about 80 people per square mile. Among counties sharing Sauk County's EPA zone, it outranks 73% of them by population. Sauk County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Sauk County's Zone 2 prediction. Sauk County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

If Sauk County tests above the action level

Mitigation cost doesn't depend on Sauk 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

Sauk County's test kit answers today; a Airthings radon monitor keeps answering for Sauk 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

Sauk 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.