Thomson, IL Radon Levels

Q: What EPA Radon Zone is Thomson in?

Thomson is in Carroll County, EPA Zone 1.

Q: How much does radon mitigation cost in Thomson?

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

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

Thomson, IL Radon Facts

EPA Radon Zone Zone 1 — High Risk > 4.0 pCi/L (Zone 1)

County Carroll County, IL

Zip Code 61285

This small community in Carroll County sits along the Mississippi River in northwestern Illinois, where river valley alluvial deposits over limestone bedrock can create variable radon conditions. Thomson's housing consists primarily of older residential properties, many dating from the early-to-mid 1900s with basement foundations typical of river communities. Given the absence of testing data for zip code 61285, homeowners should conduct radon measurements to determine individual property exposure levels.

12.00

pCi/L area average

Above EPA Action Level

Carroll County average: 12.00 pCi/L, based on 3 user-submitted tests across 1 city in the county. No homeowner readings have been submitted for Thomson itself yet, so this county figure is the closest available benchmark. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

Thomson, IL Radon Mitigation

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

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Radon Readings Near Thomson, IL

No homeowner tests have been submitted for Thomson yet. The closest cities with user-submitted radon data are shown below — explore them to gauge local conditions. Radon varies by home, so testing is the only way to know your level.

City	Distance	Avg User Level	Readings
Fulton	9.6 mi	4.00 pCi/L	1
Lanark	15.4 mi	12.00 pCi/L	3
Hanover	21.9 mi	5.00 pCi/L	1
Rock Falls	25.0 mi	6.00 pCi/L	2
Freeport	31.8 mi	3.67 pCi/L	3
Dixon	32.0 mi	14.00 pCi/L	2
Mount Morris	33.7 mi	4.00 pCi/L	1
Galena	34.7 mi	1.00 pCi/L	1

Carroll County Radon Profile

Because of its underlying geology, Carroll County is mapped as EPA Radon Zone 1 — the most elevated classification — where predicted indoor screening averages exceed 4 pCi/L. Homeowner-submitted tests from 1 city in Carroll County average 12.00 pCi/L across 3 tests — above the EPA's 4 pCi/L action level, reinforcing the need for testing across the county. As the second leading cause of lung cancer in the U.S., radon warrants testing in every Carroll County home regardless of zone or a neighbor's results.

Radon FAQ for Thomson, IL

What EPA Radon Zone is Thomson in?

Thomson and the 61285 zip code are in Carroll County, which has an EPA assigned Radon Zone of 1. A zone of 1 predicts an average indoor radon screening level greater than 4 pCi/L.

Why are radon readings shown from areas near Thomson?

No homeowner radon tests have been submitted for Thomson yet. Because radon is driven by regional soil and bedrock geology, readings from the closest cities—and the Carroll County average—are the best available indicator of local conditions until Thomson homeowners submit their own results. The EPA still recommends testing every individual home, since levels can vary significantly from house to house.

How much does radon mitigation cost in Thomson?

Radon mitigation in Thomson 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 Thomson?

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.