California, PA Radon Levels

Q: What EPA Radon Zone is California in?

California is in Washington County, EPA Zone 2.

Q: How much does radon mitigation cost in California?

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

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

California, PA Radon Facts

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

County Washington County, PA

Zip Code 15419

Located in Washington County southwest of Pittsburgh, California sits within the Appalachian Plateau where Pennsylvanian shale and sandstone formations can contribute to radon accumulation in area homes. Testing data for zip code 15419 remains sparse, making individual assessment crucial for homeowners within the Pittsburgh metropolitan region. The area's mix of older housing stock and newer suburban development creates varied foundation conditions that influence radon entry rates.

7.80

pCi/L area average

Above EPA Action Level

Washington County average: 7.80 pCi/L, based on 5 user-submitted tests across 3 cities in the county. No homeowner readings have been submitted for California 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+

California, PA 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 California, PA

No homeowner tests have been submitted for California 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
West Newton	12.4 mi	6.00 pCi/L	1
Uniontown	14.9 mi	4.00 pCi/L	1
South Park	16.8 mi	7.00 pCi/L	2
Bethel Park	19.4 mi	10.00 pCi/L	1
Mckeesport	19.8 mi	7.00 pCi/L	1
Irwin	20.0 mi	10.00 pCi/L	1
Canonsburg	20.3 mi	8.33 pCi/L	3
Washington	20.5 mi	5.00 pCi/L	1

Washington County Radon Profile

EPA mapping assigns Washington 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 Washington County average 7.80 pCi/L across 5 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 Washington County home regardless of zone or a neighbor's results.

Radon FAQ for California, PA

What EPA Radon Zone is California in?

California and the 15419 zip code are in Washington 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 California?

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

Radon mitigation in California 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 California?

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.