What EPA's radon map says about Caroline County

EPA places Caroline County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 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 Caroline County lands in the 19th percentile for radon potential.

Where Caroline County sits nationally

About 34,248 people live in Caroline County, Maryland, spread over 319.442 square miles. Averaged across its land area, Caroline County runs about 107 people per square mile. Among counties sharing Caroline County's EPA zone, it outranks 57% of them by population. Geologically, Caroline County is grouped into EPA Region 3 alongside 244 other counties that share its rock and soil setting.

What this actually means for a house in Caroline County

Caroline County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. Even at Zone 3, Caroline County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

Next steps for a home in Caroline County

Mitigation cost doesn't depend on Caroline 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 Maryland's state radon program

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

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.