Zone 1 (1): Potential for radon levels above 4 pCi/L according to EPA
Zone 2 (2): Potential for radon levels between 2 pCi/L and 4 pCi/L according to the EPA
Zone 3 (3): Lowest EPA level with expected radon levels at or below 2 pCi/L
Disclaimer: It is strongly recommended that all households, schools and office spaces test radon levels individually. The EPA Radon Zone data is not an indicator of individual test results, but a guideline for strategic planning. Toxic radon levels can be found in all counties, regardless of their zone rating. While we make efforts to keep this information up to date, it is derived from thirdparty sources which may not be accurate or reflect the most current statistics.
Missouri has 108 counties and 11 (10%) have been assigned Zone 1 counties by the EPA. Zone 1 counties have the highest potential to have homes test higher than 4 pCi/L. Missouri's state radon zone average is 1.96, which is the average of all county zone ratings the EPA has assigned the state, ranking it 31 among all states.