What EPA's radon map says about Phelps County

Phelps 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. Rank it against the rest of the country and Phelps County lands in the 54th percentile for radon potential.

Phelps County by the numbers

About 45,672 people live in Phelps County, Missouri, spread over 671.787 square miles. Population density there runs about 68 people per square mile. Among counties sharing Phelps County's EPA zone, it outranks 65% of them by population. Geologically, Phelps County is grouped into EPA Region 7 alongside 411 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 Phelps County's Zone 2 prediction. Middle-of-the-pack doesn't mean risk-free for any one Phelps County address — a moderate county average still leaves individual homes to test either side of it.

Next steps for a home in Phelps County

Mitigation cost doesn't depend on Phelps 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 Missouri's state radon program

Phelps County's test kit answers today; a Airthings radon monitor keeps answering for Phelps 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. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.