Saint Clair, MO Radon Levels

Q: What EPA Radon Zone is Saint Clair in?

Saint Clair is in Franklin County, EPA Zone 2.

Q: How much does radon mitigation cost in Saint Clair?

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

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

Saint Clair, MO Radon Facts

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

County Franklin County, MO

Zip Code 63077

Located in Franklin County southwest of St. Louis, Saint Clair sits in EPA Zone 2, indicating moderate radon potential for the 63077 zip code area. The region's Mississippian limestone bedrock and varied soil conditions can contribute to inconsistent radon levels throughout the community. While testing data remains limited, residents should consider professional radon testing to determine their individual exposure risk.

7.33

pCi/L area average

Above EPA Action Level

Franklin County average: 7.33 pCi/L, based on 3 user-submitted tests across 3 cities in the county. No homeowner readings have been submitted for Saint Clair 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+

Saint Clair, MO 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 Saint Clair, MO

No homeowner tests have been submitted for Saint Clair 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
Union	8.4 mi	13.00 pCi/L	1
Labadie	14.1 mi	4.00 pCi/L	1
Bourbon	17.5 mi	6.00 pCi/L	1
New Haven	21.9 mi	5.00 pCi/L	1
House Springs	23.1 mi	7.00 pCi/L	1
Leasburg	24.1 mi	4.00 pCi/L	1
De Soto	26.9 mi	11.00 pCi/L	1
Cuba	28.8 mi	5.00 pCi/L	1

Franklin County Radon Profile

EPA mapping assigns Franklin County to Radon Zone 2, indicating moderate predicted indoor screening levels in the 2 to 4 pCi/L range based on regional geology. Homeowner-submitted tests from 3 cities in Franklin County average 7.33 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 Franklin County home regardless of zone or a neighbor's results.

Radon FAQ for Saint Clair, MO

What EPA Radon Zone is Saint Clair in?

Saint Clair and the 63077 zip code are in Franklin 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 Saint Clair?

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

Radon mitigation in Saint Clair 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 Saint Clair?

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.