What EPA's radon map says about Allen County

EPA places Allen 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, Allen County ranks higher in radon potential than 41% of rated counties (the 41st percentile).

Allen County by the numbers

About 12,425 people live in Allen County, Kansas, spread over 500.298 square miles. Averaged across its land area, Allen County runs about 25 people per square mile. Among counties sharing Allen County's EPA zone, it outranks 25% of them by population. Geologically, Allen County is grouped into EPA Region 7 alongside 411 other counties that share its rock and soil setting.

What this actually means for a house in Allen County

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 Allen County's Zone 2 prediction. Middle-of-the-pack doesn't mean risk-free for any one Allen County address — a moderate county average still leaves individual homes to test either side of it.

If Allen County tests above the action level

Mitigation cost doesn't depend on Allen 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 Kansas's state radon program

Allen County's test kit answers today; a Airthings radon monitor keeps answering for Allen 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. Whatever zone Allen County carries, the zone explainer covers what it does and doesn't tell you about any one house.