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O Fallon, MO Radon Levels

Check local O Fallon radon levels and find certified testing and mitigation professionals to keep your home safe


O Fallon, MO Radon Facts

EPA Radon Zone Unknown Unknown
County St Charles County, MO
Zip Code 63366
Avg. User Level 7.80 pCi/L
User Tests 4

O'Fallon residents in St. Charles County face significantly elevated radon levels, with local testing showing an average of 8.67 pCi/L across zip codes 63366 and 63368. These readings substantially exceed EPA action thresholds, likely reflecting the area's limestone bedrock and glacial deposits common throughout the St. Louis Metro region. Given these elevated levels and the community's suburban housing stock with full basements, professional radon mitigation is strongly recommended for affected properties.

7.80
pCi/L average
Above EPA Action Level

Based on 4 user-submitted radon tests for homes in O Fallon, MO. The EPA recommends taking action at or above 4.0 pCi/L.

0
4.0 EPA
10+

O Fallon, MO Radon Mitigation

Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.

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O Fallon, Missouri Radon Levels

User-submitted radon test readings from homes in the O Fallon area.

Radon LevelCityHome AgeFoundationSubmitted
14 pCi/L O Fallon, MO 21-50 Years Full Basement Sep 2024
5 pCi/L O Fallon, MO 0-20 Years Full Basement Dec 2023
7 pCi/L O Fallon, MO 0-20 Years Full Basement Sep 2022

Have a radon test result for O Fallon? Submit your reading to help other homeowners.

St Charles County Radon Profile

A specific EPA radon zone has not been established for St Charles County, which is why testing is advised for all homes here irrespective of geology. Homeowner-submitted tests from 5 cities in St Charles County average 6.63 pCi/L across 8 tests — above the EPA's 4 pCi/L action level, reinforcing the need for testing across the county. Since radon is the second leading cause of lung cancer nationally, the EPA urges every household in St Charles County to test, as levels can differ between neighboring homes.

Radon FAQ for O Fallon, MO

What is the average radon level in O Fallon, MO?
Based on 4 user-submitted tests, the average radon level in O Fallon is 7.80 pCi/L. This exceeds the EPA's recommended action level of 4.0 pCi/L, and radon testing is recommended for all homes in the area.
What EPA Radon Zone is O Fallon in?
O Fallon and the 63366 zip code are in St Charles County, which has an EPA assigned Radon Zone of Unknown. A zone of Unknown does not have sufficient data for classification.
How much does radon mitigation cost in O Fallon?
Radon mitigation in O Fallon typically costs between $800 and $2,000. Most homes with standard basements can be mitigated with a sub-slab depressurization system in the $1,000–$1,500 range. Factors that can increase cost include complex foundations, crawl spaces, or very high radon levels.
Should I test for radon if I'm buying a home in O Fallon?
Yes. Radon testing should be part of every home purchase. A short-term radon test is typically included as part of the home inspection process and costs $150–$250. If elevated levels are found, you can negotiate mitigation as part of the sale.

Radon Levels Near O Fallon, MO

User-submitted radon levels from the cities closest to O Fallon with recorded test data. Explore nearby communities to compare local readings.

CityDistanceAvg User LevelSubmissions
Lake Saint Louis 2.7 mi 5.00 pCi/L 2
Saint Peters 6.1 mi 7.00 pCi/L 1
Saint Charles 9.6 mi 5.00 pCi/L 1
Chesterfield 13.4 mi 5.00 pCi/L 1
Ballwin 17.0 mi 4.00 pCi/L 1
Troy 19.1 mi 8.50 pCi/L 4
Hazelwood 19.9 mi 20.00 pCi/L 1
Labadie 20.0 mi 4.00 pCi/L 1