R
1Best Radon Mitigation Contractors in Toronto & the GTA
Last updated: By RadonIndex Research Team
RadonIndex tracks 12 radon mitigation contractors working across Toronto and the GTA, with a median 5.0★ Google rating across the 9 with three or more reviews. Installed radon mitigation typically runs $2,000–$3,000 installed according to Homeowner.ca. RadonIndex ranks every company by the RadonIndex Score, built from what it states on its own website, its Google reviews and how complete its record is, never paid placement, so the shortlist below reflects the published formula.
Where do you need radon mitigation in the GTA?
Choose your neighbourhood or city to see the ranked shortlist and local pricing for that area. RadonIndex is expanding radon mitigation coverage across the GTA. More area rankings are published as enough local businesses are listed.
Which radon mitigation contractors rank highest across the GTA?
All 12 radon mitigation contractors in the Greater Toronto and Hamilton Area, ranked by the RadonIndex Score, which combines what each company states on its own website with its Google reviews and how complete its record is.
- R2
- M3
- R4
- G5Top rated
Groundworks Foundation Repair Toronto
56/100 RadonIndex Score
Whitchurch-StouffvilleRadon Mitigation - R6
- C7
- T8
- R9
- B10
- H11
- H12
How much does radon mitigation cost in Toronto?
According to Homeowner.ca, sub-slab or sub-membrane depressurization system, material and labour runs $2,000–$3,000 installed in the GTA, while radon mitigation system, typical Canadian home runs $2,000–$4,000 installed (Homeowner.ca). Add 13% HST to any quote. The table below breaks down 7 line items, each with its own named source.
| Item | Typical range | Unit | Source |
|---|---|---|---|
| Sub-slab or sub-membrane depressurization system, material and labour | $2,000–$3,000 | installed | Homeowner.ca |
| Radon mitigation system, typical Canadian home | $2,000–$4,000(typ. $2,900) | installed | Homeowner.ca |
| Sump or drainage system depressurization | $2,000–$4,500 | installed | RenoQuotes |
| Crawl space sub-membrane depressurization | $3,000–$6,000 | installed | RenoQuotes |
| Complex or multi-system installation | $4,000–$10,000 | installed | RenoQuotes |
| HRV or ERV ventilation as a radon measure | $1,500–$3,500 | material and labour | Homeowner.ca |
| Radon fan replacement, fan only | $200–$300 | per fan | Homeowner.ca |
How does RadonIndex rank radon mitigation contractors?
Rankings can't be bought. RadonIndex gives each company one score out of 100: 40 for what it states on its own website, including a C-NRPP certification claim, 35 for its Google reviews weighted so a 5.0 on three does not outrank a 4.8 on three hundred, and 25 for how complete and reachable its record is. Across the GTA, 78% of the 9 radon mitigation contractors with three or more reviews clear 4.8★, so ranking gaps are meaningful. Positions update as the score is re-run on new data. Read our full methodology.
Questions to ask your contractor
- What is your C-NRPP certificate number, and is the certified person the one doing the work?
- Does the quote include a post-mitigation test to prove the level actually dropped? What a re-test costs
- How many suction points are you pricing, and what happens if one is not enough? Why suction points move the price
- Where will the pipe run and where does it discharge relative to windows and the roofline?
- Will you test for backdrafting of the furnace and water heater once the fan is running?
- What is the warranty on the fan, and what does it cover after year one?
Frequently asked questions
How much does radon mitigation cost in Toronto and the GTA?
- According to Homeowner.ca, sub-slab or sub-membrane depressurization system, material and labour runs $2,000–$3,000 installed, and radon mitigation system, typical Canadian home runs $2,000–$4,000 installed (Homeowner.ca). Add 13% HST to any quote. RadonIndex's radon mitigation cost guide lists every line item with its source.
How do I choose a good radon mitigation contractor in the GTA?
- Compare at least three written, itemized quotes rather than defaulting to the cheapest. RadonIndex ranks 12 radon mitigation contractors at a median 5.0★ Google rating across the 9 with three or more reviews and a median of 6 reviews among those, so start with the shortlist above, then confirm insurance and recent local references before you sign.
When is the best time to arrange radon mitigation?
- Any time of year. Mitigation is indoor work and does not have a season. What does have a sequence is the order: a three-month measurement first, the system second, and a fresh test afterwards to prove the level dropped.
Do I need a permit, and is HST included in radon mitigation quotes?
- Add 13% HST: this work is taxable in Ontario and most published prices exclude it. A residential radon system does not normally need a building permit, but the fan is an electrical installation and the vent penetrates the roof, so ask who is pulling any electrical permit and who is responsible for the roof flashing. See RadonIndex's radon mitigation cost guide for what the published ranges include.
Can companies pay to rank higher on RadonIndex?
- No. Rankings come from a published 0-100 score built from what a company states on its own website, its Google reviews and how complete its record is, never payment. Across the region, 78% of the 9 radon mitigation contractors with three or more reviews clear 4.8★. Bear in mind a Google rating measures public reputation, not competence at radon work. Full details are on our methodology page.
What should you read next?
Compare RadonIndex's other Greater Toronto and Hamilton Area service rankings, or dig into the pricing and comparison guides for this project.