Marion, IL Radon Mitigation and Testing

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

Based on 1 user-submitted tests, the average radon level is 5.00 pCi/L.

Q: What EPA Radon Zone is Marion in?

Marion is in Williamson County, EPA Zone 2.

Q: How much does radon mitigation cost in Marion?

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

Avg: 5.00 pCi/L

Williamson County

EPA Zone 2

1 user test

Located in Williamson County in southern Illinois, Marion has recorded an average radon level of 5.0 pCi/L, above the EPA's recommended action threshold. The area sits within Illinois's coal belt region, where Pennsylvanian-era coal measures and shale deposits create generally moderate radon conditions that can occasionally spike higher. Homeowners in this zip code 62959 community should consider professional radon mitigation given the documented elevated readings.

5.00

pCi/L average

Above EPA Action Level

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

4.0 EPA

10+

Marion, IL Radon Mitigation

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

Marion, IL Radon Testing

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

Marion, Illinois Radon Levels

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

Radon Level	City	Home Age	Foundation	Submitted
5 pCi/L	Marion, IL	51-99 Years	Full Basement	Mar 2021

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

Marion Radon Facts

Key details about the radon risk profile for Marion and the 62959 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

Williamson County, IL

Zip Code

62959

Predicted Screening Level

2–4 pCi/L (Zone 2)

Avg. User Submitted Level

5.00 pCi/L

User Tests Submitted

Marion and the 62959 zip code are located in Williamson 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 Marion, IL

What is the average radon level in Marion, IL?

Based on 1 user-submitted test, the average radon level in Marion is 5.00 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 Marion in?

Marion and the 62959 zip code are in Williamson 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 Marion?

Radon mitigation in Marion 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 Marion?

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