Top-rated radon detection and reduction specialists.

Get matched with top radon detection and reduction specialists in California, MD

Enter your zip and get matched with up to 5 pros

Need a pro for your radon detection and reduction project in California, MD?

Select your specific project to find the pro for you.

Verified Reviews for Radon Detection And Reduction pros in California, MD

*The Angi rating for Radon Detection And Reduction companies in California, MD is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Radon Detection And Reduction needs.

*The HomeAdvisor rating for Radon Detection And Reduction companies in California, MD is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Radon Detection And Reduction needs.

Last update on February 23, 2026

Find Radon detection and reduction specialists in California

Avatar for Radon Abatement Services
Radon Abatement Services
4.9(
256
)

Serving California, MD and surrounding areas

Approved

In business since 1998

Free estimates

Warranties offered

"I used Radon Abetment Services LLC to install a radon system in my basement. John and his team were excellent and I highly recommend them to anybody with this need. John was able via video over phone identify where the system should go. His team was extremely professional and courteous. The installation took a day and the improvement in radon levels was remarkable. We would absolutely use them again."
Additional Photos
Recommended by97%of homeowners
Request Quote
Avatar for Radon Abatement Services, LLC
Radon Abatement Services, LLC
4.6(
135
)

Serving California, MD and surrounding areas

Approved

In business since 1997

Free estimates

Customers say: Quick response

"I'm completely satisfied with the work that John's team did. They were extremely professional and knowledgeable. The workmanship is superb. Best of all, the system works as promised and reduced the radon concentration based on subsequent tests. I could not recommend them more highly."
Response time10 mins
Recommended by98%of homeowners
Request Quote
Avatar for Mid Atlantic
Mid Atlantic
4.9(
18
)

Serving California, MD and surrounding areas

In business since 1985

Free estimates

Emergency services offered

"Chris was WONDERFUL! I just purchased a home and wanted to have a mold inspection done for peace of mind. Chris took time to explain the process and put my fears at ease with his vast knowledge. He reviewed the test results with me prior to closing which gave me the peace of mind I needed to confirm I was making a good purchase and great investment. I highly recommend Mid Atlantic Commercial Residential Real Estate Solutions. VERY PROFESSIONAL AND COURTEOUS!!"
Crawl Space
Crawl Space
Crawl Space
Crawl Space
Recommended by100%of homeowners
Request Quote
Avatar for SWAT Environmental
SWAT Environmental
4.1(
91
)

Serving California, MD and surrounding areas

In business since 1988

Free estimates

Credit card accepted

"Mark did great work and made the radon abatement system blend well with the house. The office response time was slower than I would have liked, but the price and quality of work was worth the wait. All of the people I interfaced with were extremely helpful and nice. I would highly recommend this company."
Response time1 day
Recommended by90%of homeowners
Request Quote
Avatar for Green Environmental LLC
Green Environmental LLC
5.0(
9
)

Serving California, MD and surrounding areas

In business since 2013

Free estimates

Emergency services offered

"Rodney is extremely professional, easy to schedule and highly knowledgeable about lead testing! Have used him many times and will continue moving forward. Highly recommend."
Recommended by100%of homeowners
Request Quote
Avatar for Flood Crew LLC
Flood Crew LLC
4.6(
40
)

Serving California, MD and surrounding areas

In business since 2008

Free estimates

Emergency services offered

"I had a pipe burst in the basement of our rental property, Flood Crew was referred by our realtor. They arrived quickly after the pipe was fixed by our plumber, demoed, and dried out the areas, even handled packing out our furniture and placing carefully in a pod storage while the work was being done. They did mold testing and made sure everything was safe, the best part was that they dealt with the insurance and we didn’t have to do anything."
After carpets were cleaned.
Before and after of Medallion
After color sealed
Apartment carpet cleaning
Drying bathroom wood subfloor from kitchen using indirect control heat, controlled by thermostat we set in place

+57

Recommended by88%of homeowners
Request Quote
Avatar for All States Air Duct Pro
All States Air Duct Pro
3.1(
236
)

Serving California, MD and surrounding areas

In business since 1995

Free estimates

Emergency services offered

"The technicians showed up on time, were thorough and professional, and did a fantastic job in cleaning up all of the air ducts in the household. In addition, they cleaned the heating/cooling unit itself, as well as the filters, to ensure that the entire system was covered.
"
Before & After Air Duct Cleaning
Recommended by49%of homeowners
Request Quote
District Home Inspectors, LLC.
New to Angi

Serving California, MD and surrounding areas

In business since 2017

Free estimates

Credit card accepted

Welcome to District Home Inspectors. We are the premier professional Inspection company in Maryland. We offer the highest quality and most attentive customer service. We are known to pay exquisite attention to detail while making customer satisfaction our top priority. Whether your project involves minor evaluations or complete inspections, we are glad to be your number one choice. Please call us today to schedule your appointment!

Response time40 mins
Request Quote
Showing 1-10 of 14
Radon Detection and Reduction questions, answered by experts

The soil beneath your house is most likely what’s causing an increased level of radon. This is because soil holds radioactivity for a long time and it’s also what most buildings are built on. Another common source of radon is water from a source that hasn’t been through periodic radon tests, such as well water. Over time, the radon from the soil can inhabit other parts of your house like the foundation or plumbing.

The average radon mitigation system uses about 876 kWh of electricity per year, although the exact amount of electricity used will vary depending on the size of the radon fan. Once the system is installed, the annual increase to your energy bill could range from $30 to $300 per year, again depending on the size of the fan.

Keeping radon from getting into your home is much better than having to get rid of it once it's already indoors. While there may not be a way to fully prevent radon from getting into your home, there are things you can do to reduce the gas's ability to enter. 

Sealing foundation cracks and openings can help keep the gas from seeping inside. Improving air flow, such as by opening windows, can also be helpful. If you're building your home from scratch, talk to your contractor about using radon-resistant construction to keep the gas out.

You'll need to test your home for radon after installing the mitigation system, then again every two years. If radon remains elevated, contact a licensed radon professional, either the contractor who installed the system or a different one, and have them evaluate the system. They may need to make some changes to improve its effectiveness and performance.

Your radon fan needs to operate 24/7 to be effective. The only time the fan isn't operating is during its replacement. Radon levels in the home can increase within hours if the fan stops working or something obstructs the stack vent. Fortunately, radon systems require no downtime maintenance between fan changes.

The California, MD homeowners’ guide to radon detection and reduction services

From average costs to expert advice, get all the answers you need to get your job done.

See all articles