What EPA's radon map says about Warren County

EPA places Warren 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, Warren County ranks higher in radon potential than 53% of rated counties (the 53rd percentile).

Where Warren County sits nationally

About 37,373 people live in Warren County, Pennsylvania, spread over 884.293 square miles. Population density there runs about 42 people per square mile. Among counties sharing Warren County's EPA zone, it outranks 59% of them by population. Warren County falls in EPA Radon Region 3, one of 245 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Warren County

Warren County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). Middle-of-the-pack doesn't mean risk-free for any one Warren County address — a moderate county average still leaves individual homes to test either side of it.

Testing and mitigation in Warren County

Mitigation cost doesn't depend on Warren 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 Pennsylvania's state radon program

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

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.