O Fallon, IL Radon Mitigation and Testing

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

Based on 1 user-submitted tests, the average radon level is 6.00 pCi/L.

Q: What EPA Radon Zone is O Fallon in?

O Fallon is in St Clair County, EPA Zone 2.

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: 6.00 pCi/L

St Clair County

EPA Zone 2

1 user test

Located in St. Clair County on the Illinois side of the St. Louis Metro, O'Fallon shows a concerning average radon level of 6.0 pCi/L, which exceeds the EPA action threshold. This elevated reading reflects the area's geological conditions, including Mississippi River floodplain deposits over limestone bedrock. Homeowners in zip code 62269 should prioritize professional radon testing and consider mitigation systems if levels exceed 4.0 pCi/L.

6.00

pCi/L average

Above EPA Action Level

Based on 1 user-submitted radon test for homes in O Fallon, IL. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

O Fallon, IL Radon Mitigation

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

O Fallon, IL Radon Testing

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

O Fallon, Illinois Radon Levels

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

Radon Level	City	Home Age	Foundation	Submitted
6 pCi/L	O Fallon, IL	0-20 Years	Full Basement	Nov 2021

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 62269 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

St Clair County, IL

Zip Code

62269

Predicted Screening Level

2–4 pCi/L (Zone 2)

Avg. User Submitted Level

6.00 pCi/L

User Tests Submitted

O Fallon and the 62269 zip code are located in St Clair County, which has an EPA assigned Radon Zone of 2. A radon zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for O Fallon, IL

What is the average radon level in O Fallon, IL?

Based on 1 user-submitted test, the average radon level in O Fallon is 6.00 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 62269 zip code are in St Clair County, which has an EPA assigned Radon Zone of 2. A zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L.

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 Illinois

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

City	Avg User Radon Level	Submissions
Buffalo Grove	6.10 pCi/L	10
Crystal Lake	7.25 pCi/L	8
Lake Zurich	6.00 pCi/L	7
Grayslake	5.00 pCi/L	7
New Lenox	10.17 pCi/L	6
Park Ridge	7.00 pCi/L	6
Arlington Heights	6.17 pCi/L	6
Waterloo	9.20 pCi/L	5
Palatine	7.80 pCi/L	5
Round Lake	7.80 pCi/L	5
Northbrook	6.20 pCi/L	5
Mchenry	11.00 pCi/L	4
Dekalb	8.75 pCi/L	4
Columbia	8.00 pCi/L	4
Lisle	7.25 pCi/L	4
Normal	7.25 pCi/L	4
Antioch	7.00 pCi/L	4
Elk Grove Village	7.00 pCi/L	4
Aurora	6.75 pCi/L	4
Hoffman Estates	6.75 pCi/L	4