Putnam County, MO radon potential
EPA places Putnam 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. Rank it against the rest of the country and Putnam County lands in the 36th percentile for radon potential.
Where Putnam County sits nationally
Putnam County, Missouri is home to about 4,539 people across 517.319 square miles. Population density there runs about 9 people per square mile. Within its own EPA zone, Putnam County is bigger by population than 8% of the counties that share it. EPA's geology-based Region 7 groups Putnam County with 411 other counties nationally sharing its underlying rock and soil profile.
Zone vs. an actual test
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 Putnam County's Zone 2 prediction. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Putnam County — testing is the only way to know an individual home's actual level.
Next steps for a home in Putnam County
A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.
Find Missouri's state radon program
For Putnam County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Putnam County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.
Where Putnam County's figures come from
Putnam County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.