California, MD Radon Mitigation and Testing

Q: What is the average radon level in California, MD?

Based on 1 user-submitted tests, the average radon level is 5.00 pCi/L.

Q: What EPA Radon Zone is California in?

California is in St Mary's County, EPA Zone Unknown.

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.

Avg: 5.00 pCi/L

St Mary's County

EPA Zone Unknown

1 user test

Based in St Mary's County on Maryland's Western Shore, California has recorded an average radon level of 5.0 pCi/L, which exceeds the EPA action level and indicates the need for mitigation consideration. The area's Coastal Plain geology, featuring sand, clay, and gravel deposits over deeper formations, creates conditions that can concentrate radon in homes throughout zip code 20619. Properties near the Patuxent River Naval Air Station should particularly prioritize testing and mitigation.

5.00

pCi/L average

Above EPA Action Level

Based on 1 user-submitted radon test for homes in California, MD. The EPA recommends taking action at or above 4.0 pCi/L.

4.0 EPA

10+

California, MD Radon Mitigation

Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.

California, MD Radon Testing

Finding qualified radon testing professionals is the first step toward protecting your home.

California, Maryland Radon Levels

User-submitted radon test readings from homes in the California area.

Radon Level	City	Home Age	Foundation	Submitted
5 pCi/L	California, MD	0-20 Years	Full Basement	May 2019

Have a radon test result for California? Submit your reading to help other homeowners.

California Radon Facts

Key details about the radon risk profile for California and the 20619 zip code area.

EPA Radon Zone

Unknown

County

St Mary's County, MD

Zip Code

20619

Predicted Screening Level

Unknown

Avg. User Submitted Level

5.00 pCi/L

User Tests Submitted

California and the 20619 zip code are located in St Mary's County, which has an EPA assigned Radon Zone of Unknown. A radon zone of Unknown does not have sufficient data for classification. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for California, MD

What is the average radon level in California, MD?

Based on 1 user-submitted test, the average radon level in California is 5.00 pCi/L. This exceeds the EPA's recommended action level of 4.0 pCi/L, and radon testing is recommended for all homes in the area.

What EPA Radon Zone is California in?

California and the 20619 zip code are in St Mary's County, which has an EPA assigned Radon Zone of Unknown. A zone of Unknown does not have sufficient data for classification.

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.

Most Active Radon Markets in Maryland

Cities with the most user-submitted radon test data in the state.

City	Avg User Radon Level	Submissions
Frederick	8.29 pCi/L	7
Potomac	9.00 pCi/L	6
Hagerstown	8.67 pCi/L	6
Westminster	14.50 pCi/L	4
Baltimore	7.00 pCi/L	4
Annapolis	4.25 pCi/L	4
Upper Marlboro	15.00 pCi/L	3
Edgewater	12.67 pCi/L	3
Bowie	9.00 pCi/L	3
Clarksburg	8.00 pCi/L	3
Gambrills	6.00 pCi/L	3
Elkton	5.33 pCi/L	3
Silver Spring	4.33 pCi/L	3
Chesapeake Beach	14.00 pCi/L	2
Cumberland	9.00 pCi/L	2
Frostburg	9.00 pCi/L	2
Owings	5.50 pCi/L	2
Huntingtown	4.50 pCi/L	2
Mc Henry	20.00 pCi/L	1
Mount Airy	20.00 pCi/L	1