RadonIndex

Radon testing and mitigation, Greater Toronto and Hamilton Area

Every company here says on its own website that it does radon work, and we show you the wording that got it listed. Reach any of them from its profile. No shared leads, and nobody paid to be here.

Browse the companiesBrowse cost guides

Last updated: By RadonIndex Research Team

35
Greater Toronto and Hamilton Area businesses
2
Service categories
4.9★
Avg rating, pros carrying one

What does RadonIndex cover?

Two things, because radon work splits cleanly in two. Measurement tells you whether you have a problem; mitigation fixes it. Some companies do both, most do one. The 35 businesses below came out of a Google Maps sweep of the Greater Toronto and Hamilton Area that returned 138 candidates. We read each company's own website and kept the ones whose pages name a radon service. Every one of the 103 drops carries a written reason, and the biggest group is not what you might expect: 61 had no readable website at all, so we could not look rather than looked and found nothing. Another 26 sit outside the region. Ranking comes from the RadonIndex Score, which combines what each company states on its own website, its Google reviews, and how complete its record is. Pick a service to see the list, the published Canadian price ranges, and what to ask before you hire.

What does radon work cost?

A sub-slab or sub-membrane depressurization system, material and labour runs $2,000 to $3,000 installed, according to Homeowner.ca, while a complex or multi-system installation runs $4,000 to $10,000 (RenoQuotes). Testing is far cheaper: a long-term kit with lab analysis is $30 to $60.

Every figure in our cost guides is a published Canadian range, and each one is re-checked against a cached copy of the page it is attributed to before it can appear. None of them is specific to this region, because no published source gives one, and we would rather say so than invent a local number. We hold no pricing from the companies listed here.

See all RadonIndex cost guides

The highest-ranked radon companies right now

Ranked by the RadonIndex Score

These 8 sit highest on the RadonIndex Score, which is built from what each company states on its own website, its Google reviews, and how complete its record is. It is not a certification check and it is not a measure of technical competence at radon work. Every card shows the score, up to two of the statements behind it, the real rating and a direct way to reach the company.

Which municipalities have listed companies?

Companies publish a real street address in 11 municipalities, read from the address itself rather than from a nearest-point guess. Only the municipalities with enough listings to be worth reading get their own area page; the deepest are Toronto (7), Vaughan (4). Radon is a small trade, so most of those 11 municipalities hold one or two companies. Companies that publish no address at all, which is common for service-area businesses, appear in the category lists instead of on an area page, because we genuinely do not know where they are based.

Browse all municipalities

How does RadonIndex work?

Test first, then fix, then prove the fix worked. Everything on this site is free to browse, we take no commission, and every listing shows how to reach the company itself.

  1. 1. Measure for three months

    A long-term kit costs $30 to $60. Radon swings hour to hour, so a short test describes a few days rather than your house.

  2. 2. Check the published ranges

    A standard system is $2,000 to $3,000 under the Health Canada guide range. Knowing that before you call is most of the negotiation.

  3. 3. Reach two of them yourself

    Ask for the C-NRPP certificate number and whether the quote includes a re-test after the system runs. Then compare.

How does RadonIndex rank companies?

Every company gets one published RadonIndex Score out of 100, and the list is sorted on it. It has three parts: what the company states on its own website, worth 40; its Google reviews, worth 35; and how complete and reachable its record is, worth 25. The largest part is what a company says about itself because radon has a real certifier: a stated C-NRPP certification is the one claim here you can go and check yourself against a public register, and every profile prints the sentence we found it in. Reviews still count, and the rating is weighted for how many reviews stand behind it so a 5.0 on four cannot leapfrog a 4.8 on three hundred. No company can buy a higher position, and the method is identical for all 35 listings.

Read the full methodology

What should you ask before hiring a radon contractor?

Radon work is unusual in that you cannot see whether it worked. These questions are the ones that decide whether you end up with a system that measurably lowered the level, or a fan on a pipe and no evidence either way.

RadonIndex questions, answered

How does a company get listed on RadonIndex?

We swept public Google Maps data for the Greater Toronto and Hamilton Area, then read each business's own website. A business is listed only when that site names a radon service - testing, measurement, inspection, mitigation, removal or reduction. A page that merely mentions radon in passing is not enough, which is why 35 businesses are listed out of the 138 that came back from the sweep. Every exclusion is recorded with a reason, and most of the excluded were dropped because their website could not be read at all rather than because it said nothing about radon.

Does a listing mean the company is certified?

No. Certification under the Canadian National Radon Proficiency Program is held by a person, not automatically by the company employing them. We mark a listing as claiming C-NRPP certification only when we found that claim in the company's own website text, and we show you the sentence. Verify it directly with C-NRPP before you hire.

Which areas does RadonIndex cover?

The Greater Toronto and Hamilton Area. 35 businesses across 2 service categories, with 11 municipalities carrying a published address. Coverage is honestly thin in places: several municipalities have a single listed business, and companies that publish no address at all appear in the category lists rather than on an area page.

How current is the data?

Ratings and review counts come from public Google Maps data collected for the August 2026 dataset, averaging 4.9 stars across the companies carrying a Google rating. Prices in the cost guides come from named published Canadian sources, and every figure is re-checked against a cached copy of the page it is attributed to.