Alton, IL Radon Levels

Q: What EPA Radon Zone is Alton in?

Alton is in Madison County, EPA Zone 2.

Q: Why are radon readings shown from areas near Alton?

No homeowner radon tests have been submitted for Alton yet, so readings from the closest cities and the Madison County average are used as the best available indicator of local conditions. The EPA recommends testing every individual home.

Q: How much does radon mitigation cost in Alton?

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

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

Alton, IL Radon Facts

EPA Radon Zone Zone 2 — Moderate Risk 2–4 pCi/L (Zone 2)

County Madison County, IL

Zip Code 62002

Situated along the Mississippi River bluffs in Madison County, Alton's location on the Illinois side of the St. Louis Metro exposes homes to variable radon conditions from river valley deposits and underlying limestone. While specific testing data is limited for the 62002 zip code, the geological setting warrants homeowner testing across this historic river town.

5.44

pCi/L area average

Above EPA Action Level

Madison County average: 5.44 pCi/L, based on 9 user-submitted tests across 8 cities in the county. No homeowner readings have been submitted for Alton 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+

Alton, 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 Alton, IL

No homeowner tests have been submitted for Alton 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
Godfrey	3.7 mi	6.00 pCi/L	1
East Alton	4.4 mi	4.00 pCi/L	1
Granite City	12.9 mi	8.00 pCi/L	1
Glen Carbon	14.3 mi	2.50 pCi/L	2
Grafton	16.1 mi	14.00 pCi/L	1
Maryville	16.9 mi	11.00 pCi/L	1
Jerseyville	17.5 mi	3.50 pCi/L	2
Collinsville	18.1 mi	5.00 pCi/L	1

Madison County Radon Profile

The soils and bedrock of Madison County place it in EPA Radon Zone 2, a moderate-risk classification with predicted indoor averages of 2 to 4 pCi/L. Homeowner-submitted tests from 8 cities in Madison County average 5.44 pCi/L across 9 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 Madison County to test, as levels can differ between neighboring homes.

Radon FAQ for Alton, IL

What EPA Radon Zone is Alton in?

Alton and the 62002 zip code are in Madison 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.

Why are radon readings shown from areas near Alton?

No homeowner radon tests have been submitted for Alton yet. Because radon is driven by regional soil and bedrock geology, readings from the closest cities—and the Madison County average—are the best available indicator of local conditions until Alton 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 Alton?

Radon mitigation in Alton 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 Alton?

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.