Clinton County, MO radon potential
EPA's own radon map rates Clinton County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 83rd percentile for radon potential — Clinton County outranks 83% of every county EPA has rated.
Clinton County by the numbers
Clinton County, Missouri is home to about 21,721 people across 418.94 square miles. That works out to roughly 52 people per square mile. Within its own EPA zone, Clinton County is bigger by population than 49% of the counties that share it. Clinton County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.
Why the zone isn't the answer by itself
Where the national indoor average runs about 1.3 pCi/L, Clinton County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Clinton County will test well under the action level, and EPA's guidance is to test regardless of zone.
Testing and mitigation in Clinton 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 Clinton County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Clinton County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.
Where Clinton County's figures come from
Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Clinton County carries, the zone explainer covers what it does and doesn't tell you about any one house.