What EPA's radon map says about Oakland County

EPA places Oakland 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 that's the 66th percentile for radon potential — Oakland County outranks 66% of every county EPA has rated.

How Oakland County compares

About 1,296,888 people live in Oakland County, Michigan, spread over 867.426 square miles. Population density there runs about 1,495 people per square mile. Among counties sharing Oakland County's EPA zone, it outranks 99% of them by population. Geologically, Oakland County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

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 Oakland County's Zone 2 prediction. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Oakland County — testing is the only way to know an individual home's actual level.

Next steps for a home in Oakland County

Mitigation cost doesn't depend on Oakland 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 Michigan's state radon program

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

Oakland County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Oakland County carries, the zone explainer covers what it does and doesn't tell you about any one house.