Saint Louis, MO Radon Levels

Q: What EPA Radon Zone is Saint Louis in?

Saint Louis is in St Louis City County, EPA Zone Unknown.

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

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

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

Saint Louis, MO Radon Facts

EPA Radon Zone Unknown Unknown

County St Louis City County, MO

Zip Code 63101

Spanning multiple zip codes (63101-63109) in St. Louis City, Missouri's historic urban core sits on Mississippi River bluff limestone and alluvial deposits. The city's diverse housing ranges from century-old brick buildings to modern developments, with basement configurations varying significantly by neighborhood. While comprehensive testing data is limited across these zip codes, the underlying limestone geology warrants radon testing for all property types throughout the metropolitan area.

12.20

pCi/L area average

Above EPA Action Level

St Louis City County average: 12.20 pCi/L, based on 5 user-submitted tests across 4 cities in the county. No homeowner readings have been submitted for Saint Louis 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 Louis, 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 Louis, MO

No homeowner tests have been submitted for Saint Louis 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
Hazelwood	10.5 mi	20.00 pCi/L	1
Fenton	13.1 mi	16.00 pCi/L	2
Ballwin	13.4 mi	4.00 pCi/L	1
Chesterfield	14.8 mi	5.00 pCi/L	1
Arnold	15.1 mi	10.50 pCi/L	2
Saint Charles	16.5 mi	5.00 pCi/L	1
Imperial	17.6 mi	13.00 pCi/L	1
Saint Peters	19.9 mi	7.00 pCi/L	1

St Louis City County Radon Profile

A specific EPA radon zone has not been established for St Louis City County, which is why testing is advised for all homes here irrespective of geology. Few homeowner tests have been logged inside St Louis City County so far, which is why this page draws on the nearest recorded readings to illustrate regional radon levels. Since radon is the second leading cause of lung cancer nationally, the EPA urges every household in St Louis City County to test, as levels can differ between neighboring homes.

Radon FAQ for Saint Louis, MO

What EPA Radon Zone is Saint Louis in?

Saint Louis and the 63101 zip code are in St Louis City County, which has an EPA assigned Radon Zone of Unknown. A zone of Unknown does not have sufficient data for classification.

Why are radon readings shown from areas near Saint Louis?

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

Radon mitigation in Saint Louis 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 Louis?

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.