Best Radon Testing & Mitigation in Markham

About Radon in Markham, Ontario

Last updated: March 2026

Markham is served by C-NRPP certified radon professionals listed on RadonFinder.ca. Ontario has widely varying radon risk depending on geography. The Ottawa Valley, eastern Ontario, and areas underlain by the Canadian Shield, including parts of Sudbury, Elliot Lake, and the Bancroft region, have elevated radon due to uranium-rich granite bedrock. Southern Ontario's clay and limestone geology generally produces lower levels, though local hotspots exist in any region. The 2024 Cross-Canada survey found about 13% of Ontario homes exceed the guideline.

Typical Mitigation Cost in Ontario

$2,200–$3,800

Near national average

Costs vary significantly between the GTA, Ottawa, and northern Ontario due to labour markets and home construction types.

•Foundation type: poured concrete, block, or slab
•Basement finish level: unfinished installs are faster and cheaper
•Pipe routing complexity in finished or split-level homes
•GTA vs. rural Ontario labour rate differences
•Age of home: older homes may require additional sealing work

Showing 1–16 of 21 professionals in Markham

BGIS

Markham, ON

3.5(121)Google

BGIS is a C-NRPP certified radon testing and mitigation professional serving Markham, ON and across ON. They offer complete radon solutions from initial testing through to mitigation system installation.

TestingMitigation

647-995-7638Call View Profile

RadonClean

Markham, ON

Provides DIY and official radon measurement, testing, and mitigation system installation. Services offered for homeowners, real estate, and new built houses.

TestingMitigation

(416) 898-8127Call View Profile

RnP

Markham, ON

Testing

View Profile

Rival Home Inspections

Ajax, ON

5.0(209)Google

Offers radon services. Serves Ajax, ON, Toronto, Durham, York, Peel, Halton, Simcoe, Brant, Dufferin, Kawartha Lakes, Hamilton, Waterloo, Peterborough, and all GTA Regions.

Testing

(905) 922-5437Call View Profile

Energy Home Service Corp.

Vaughan, ON

Energy Home Service Corp. is a C-NRPP certified radon testing professional serving Vaughan, ON and across ON. Their certified inspectors provide accurate radon measurements for homes and businesses.

Testing

(647) 291-1646Call View Profile

Borts Home and Energy

Etobicoke, ON

4.8(292)Google

Borts Home and Energy is a C-NRPP certified radon testing and mitigation professional serving Etobicoke, ON. They offer complete radon solutions from initial testing through to mitigation system installation.

TestingMitigation

(416) 880-7620Call View Profile

The Bearstar Group Inc

North York, ON

4.3(6)Google

Offers hazardous material abatement services including radon solutions for commercial, industrial, and institutional buildings. Provides identification, removal, and disposal with 25+ years expertise.

TestingMitigation

(905) 484-9798Call View Profile

Expert Plumbing and Drains Inc

Burlington, ON

5.0(222)Google

A full-service plumbing and drain company offering heating and radon services. Brings over 80 years of combined experience to homeowners and custom home builders.

Testing

(905) 531-4111Call View Profile

ECOH Management Inc.

Toronto, ON

5.0(6)Google

ECOH Management Inc. is a C-NRPP certified radon testing professional serving Toronto, ON. Their certified inspectors provide accurate radon measurements for homes and businesses.

Testing

(416) 786-9746Call View Profile

Canada Post

Mississauga, ON

2.2(191)Google

Canada Post is a C-NRPP certified radon testing professional serving Mississauga, ON. Their certified inspectors provide accurate radon measurements for homes and businesses.

Testing

(416) 909-6969Call View Profile

WSP Canada

Etobicoke, ON

4.8(12)Google

WSP Canada is a C-NRPP certified radon testing and mitigation professional serving Etobicoke, ON. They offer complete radon solutions from initial testing through to mitigation system installation.

TestingMitigation

(647) 299-6692Call View Profile

Radiation Safety Institute of Canada, National Laboratories

Toronto, ON

3.8(8)Google

The Radiation Safety Institute of Canada's National Laboratories in Toronto offer radiation safety training and lab services. For radon, it runs a radon chamber and CRM calibration for professionals and no longer offers home radon testing to the public.

Testing

(416) 650-9090Call View Profile

ECOH

Mississauga, ON

5.0(6)Google

ECOH is a C-NRPP certified radon testing professional serving Mississauga, ON. Their certified inspectors provide accurate radon measurements for homes and businesses.

Testing

(905) 795-2800Call View Profile

Martech Group Inc.

Mississauga, ON

5.0(21)Google

Martech Group Inc. is a C-NRPP certified radon testing professional serving Mississauga, ON. Their certified inspectors provide accurate radon measurements for homes and businesses.

Testing

(416) 801-0593Call View Profile

AmeriSpec of Barrie, Orillia and Muskoka

Barrie, ON

AmeriSpec of Barrie, Orillia and Muskoka is a C-NRPP certified radon testing professional serving Barrie, ON. Their certified inspectors provide accurate radon measurements for homes and businesses.

Testing

(705) 722-5876Call View Profile

Accurate Construction

Acton, ON

4.1(13)Google

Accurate Construction Ltd. mainly repairs basement foundation cracks from inside using polyurethane injection, and also installs radon mitigation systems to lower indoor radon levels. It serves over 30 Ontario communities from Hamilton to Barrie and Vaughan to Oshawa.

Testing

(519) 853-3966Call View Profile

Local radon data

How common is high radon in Markham?

Lower

1 in 59

homes tested in the Markham area had radon above Health Canada's action level of 200 Bq/m³. Your home can be very different from its neighbours, so the only way to know your level is to test.

Markham

1 in 59

Ontario

1 in 7.6

Canada

1 in 5.6

Postal areas nearby with the highest estimates

256 homes tested in the 2024 Cross-Canada survey. Source: the RadonFinder.ca radon map of Canada, built on the 2024 Cross-Canada survey, Health Canada data and Statistics Canada census data.

Open Markham on the radon map

Test before you call a pro

Know your radon level in Markham first

A home monitor tells you whether you need mitigation at all, and later confirms it worked. Health Canada bases decisions on a 3-month average, ideally through winter.

Best Overall

Airthings Corentium Home

~$170–190 CAD C-NRPP tested

View on Amazon.ca

Newest Model

Airthings Corentium Home 2

~$230–250 CAD

View on Amazon.ca

Compare all detectors · As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.

Frequently Asked Questions: Radon in Markham

RadonFinder.ca lists C-NRPP certified radon testing and mitigation professionals serving Markham, Ontario. Browse the directory above to compare professionals by services offered, certifications, and reviews.

Most homeowners in Ontario pay between $2,200 and $3,800 for a complete radon mitigation system. Actual cost depends on your foundation type, home size, and the complexity of the installation. Request quotes from multiple professionals to compare.

Markham follows Health Canada's national guideline of 200 Bq/m³. If your home tests above this level, Health Canada recommends taking action to reduce radon within two years for levels between 200 and 600 Bq/m³, and within one year if above 600 Bq/m³.

Yes. Health Canada recommends testing every home in Canada, regardless of age, construction type, or location. Radon levels vary from house to house and even neighbouring homes can have very different readings. A long-term test of at least 91 days during the heating season is the most reliable method.

The most common system is active sub-slab depressurization (ASD). A certified professional installs a pipe through your foundation slab connected to a fan that draws radon from beneath the home and vents it safely above the roofline. Installation typically takes one day.