Philadelphia, TN Radon Levels

Q: What EPA Radon Zone is Philadelphia in?

Philadelphia is in Loudon County, EPA Zone 1.

Q: How much does radon mitigation cost in Philadelphia?

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

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

Philadelphia, TN Radon Facts

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

County Loudon County, TN

Zip Code 37846

Nestled in Loudon County within the Knoxville metro area, Philadelphia sits atop Tennessee's Ridge and Valley geological province where limestone bedrock can contribute to radon formation. Testing data for this East Tennessee community remains limited, making professional radon assessment crucial for homeowners. The area's mix of older homes and newer construction, combined with the region's geological characteristics, suggests that individual testing should be a priority for all residents.

8.50

pCi/L area average

Above EPA Action Level

Loudon County average: 8.50 pCi/L, based on 2 user-submitted tests across 2 cities in the county. No homeowner readings have been submitted for Philadelphia 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+

Philadelphia, TN 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 Philadelphia, TN

No homeowner tests have been submitted for Philadelphia 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
Loudon	6.1 mi	9.00 pCi/L	1
Lenoir City	13.5 mi	8.00 pCi/L	1
Vonore	17.3 mi	9.00 pCi/L	1
Athens	18.1 mi	15.00 pCi/L	1
Maryville	25.1 mi	10.50 pCi/L	2
Oak Ridge	25.2 mi	7.00 pCi/L	2
Oliver Springs	25.2 mi	6.00 pCi/L	1
Knoxville	32.0 mi	4.00 pCi/L	1

Loudon County Radon Profile

Because of its underlying geology, Loudon 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 2 cities in Loudon County average 8.50 pCi/L across 2 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 Loudon County home regardless of zone or a neighbor's results.

Radon FAQ for Philadelphia, TN

What EPA Radon Zone is Philadelphia in?

Philadelphia and the 37846 zip code are in Loudon 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 Philadelphia?

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

Radon mitigation in Philadelphia 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 Philadelphia?

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.