Gray Summit, MO Radon Levels

Q: What EPA Radon Zone is Gray Summit in?

Gray Summit is in Franklin County, EPA Zone 2.

Q: How much does radon mitigation cost in Gray Summit?

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

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

Gray Summit, MO Radon Facts

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

County Franklin County, MO

Zip Code 63039

This Franklin County community within the St. Louis metropolitan area sits on Missouri's Ozark fringe, where limestone bedrock and karst features create conditions favorable for radon gas production and accumulation. Although testing data for zip code 63039 is currently limited, the area's geological characteristics suggest residents should test their homes for radon. Properties built over the region's extensive limestone formations may experience elevated radon levels through natural fractures and cave systems.

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 Gray Summit 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+

Gray Summit, 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 Gray Summit, MO

No homeowner tests have been submitted for Gray Summit 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
Labadie	2.8 mi	4.00 pCi/L	1
Union	11.1 mi	13.00 pCi/L	1
House Springs	16.0 mi	7.00 pCi/L	1
Ballwin	16.7 mi	4.00 pCi/L	1
Chesterfield	16.7 mi	5.00 pCi/L	1
Fenton	19.5 mi	16.00 pCi/L	2
Lake Saint Louis	20.2 mi	5.00 pCi/L	2
O Fallon	20.3 mi	7.75 pCi/L	4

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 Gray Summit, MO

What EPA Radon Zone is Gray Summit in?

Gray Summit and the 63039 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 Gray Summit?

No homeowner radon tests have been submitted for Gray Summit 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 Gray Summit 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 Gray Summit?

Radon mitigation in Gray Summit 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 Gray Summit?

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.