O Fallon, MO Radon Mitigation and Testing

Q: What is the average radon level in O Fallon, MO?

Based on 4 user-submitted tests, the average radon level is 7.80 pCi/L.

Q: What EPA Radon Zone is O Fallon in?

O Fallon is in St Charles County, EPA Zone Unknown.

Q: How much does radon mitigation cost in O Fallon?

Radon mitigation typically costs between $800 and $2,000. Most standard systems fall in the $1,000-$1,500 range.

Avg: 7.80 pCi/L

St Charles County

EPA Zone Unknown

4 user tests

O Fallon is located in St Charles County, Missouri. With 4 user-submitted readings averaging 7.80 pCi/L, the area exceeds the EPA's 4.0 pCi/L action threshold, and testing is strongly recommended for homeowners in the 63366 zip code.

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.

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.

O Fallon, MO Radon Testing

Finding qualified radon testing professionals is the first step toward protecting your home.

O Fallon, Missouri Radon Levels

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

Radon Level	City	Home Age	Foundation	Submitted
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.

O Fallon Radon Facts

Key details about the radon risk profile for O Fallon and the 63366 zip code area.

EPA Radon Zone

Unknown

County

St Charles County, MO

Zip Code

63366

Predicted Screening Level

Unknown

Avg. User Submitted Level

7.80 pCi/L

User Tests Submitted

O Fallon and the 63366 zip code are located in St Charles County, which has an EPA assigned Radon Zone of Unknown. A radon zone of Unknown does not have sufficient data for classification. The EPA recommends testing every home regardless of zone classification.

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.

Most Active Radon Markets in Missouri

Cities with the most user-submitted radon test data in the state.

City	Avg User Radon Level	Submissions
Troy	8.50 pCi/L	4
Lees Summit	7.00 pCi/L	3
Columbia	3.00 pCi/L	2
House Springs	7.00 pCi/L	1
Kansas City	7.00 pCi/L	1
Springfield	7.00 pCi/L	1
Independence	5.00 pCi/L	1
Wentzville	No submissions	0