Radon Mitigation Cost in Ontario: What You'll Actually Pay in 2026
A radon mitigation system in Ontario should cost you between $2,800 and $3,800. Most of the time. For most homes.
But quotes in the wild swing from $2,200 to over $7,000 for the same basic job. The price gap isn’t random. It’s a mix of foundation type, fan placement, finished space, and a few installers charging premiums because they can.
This guide breaks down what you should pay, what makes the price move, and the warranties and grants that can cover some or all of the bill in Ontario.
The short version:
- Typical Ontario mitigation runs $2,800 to $3,800 for a single-family home
- Crawl spaces, finished basements, and large homes push toward the high end
- Quotes above $5,000 are a yellow flag unless you have real complications
- Tarion warranty pays up to $50,000 for post-February 2021 builds in Ontario
- The Lungs Matter Grant covers up to $1,500 for income-eligible homeowners
- DIY mitigation is legal but rarely smart. A handful of small tasks are safe to do alone.
The Ontario mitigation cost range
Our published price for a standard Ontario home is $2,800 to $3,800 flat. That covers the install, the post-mitigation verification test, and a 5-year workmanship warranty.
Most reputable Ontario installers land in the same range. Quotes from C-NRPP certified mitigators in 2026 cluster around $3,000 to $4,000 across the GTA, Hamilton, Kitchener-Waterloo, Guelph, London, and Ottawa.
A few specifics fall outside that range:
- Below $2,800: rare, but a simple basement with a short pipe run and a side-wall exhaust can land at $2,500 or so
- Above $3,800: usually means a crawl space, multiple foundations, long pipe run through finished space, or a luxury finish
- Above $5,000: treat as a yellow flag. Get a second quote.
- Above $7,000: almost always overpriced unless the home is huge or has rare structural issues
Health Canada’s measurement and mitigation protocols are the same across the country.
What actually changes the price
Six things move the number within (or outside) our $2,800 to $3,800 range.
| Cost driver | Cheaper end | More expensive end |
|---|---|---|
| Foundation type | Single full basement | Crawl space, partial slab, multiple foundations |
| Home size | Under 2,000 sq ft | Over 3,500 sq ft (often needs 2+ suction points) |
| Pipe routing | Short run, exits side wall | Long run through finished living space |
| Fan placement | Exterior on side wall | Attic or roof, longer run, more flashing |
| Sump pit | None, or simple sealed cover | Active suction tied into the pit |
| Aesthetics | Pipe exposed in unfinished basement | Pipe boxed into closets or chases |
Two of these matter more than the others.
Foundation type is the biggest single driver. A clean full basement is straightforward. A crawl space needs a sealed membrane and sub-membrane depressurization, which costs more in materials and labour. Homes with mixed foundations (basement plus crawl space, or basement plus slab-on-grade addition) often need two suction points instead of one.
Pipe routing through finished space costs more. Routing a pipe through an unfinished basement, up a utility chase, and out the side wall is fast. Routing it through a finished basement bathroom, up through a finished closet on the main floor, and out through the roof is slow. Both options work. The second adds labour and drywall patching.
Why some Ontario quotes hit $5,000+
Three patterns show up most often when a quote feels high.
1. The installer assumes the worst case
Some installers price every quote as if your home will need two suction points and a complex pipe run. They build in contingency they may never use. Their average price across all jobs sits at $4,500 to $5,500.
A C-NRPP CRMT installer should do a site visit before quoting. The visit takes 30 minutes. If a “quote” arrives without a site visit, treat the number as a placeholder.
2. Brokerage markup
A growing number of “radon companies” in Ontario don’t do the work themselves. They take your inquiry, get three quotes from local subs, mark up by 30 to 50 percent, and pass the job along.
You’re paying for their lead-gen budget. Not for better work.
3. Luxury aesthetic finishes
A pipe boxed into matching trim through a finished basement gym takes a carpenter half a day. That’s $500 to $800 added to the bill, fairly. Some installers charge $1,500 to $2,500 for the same finish.
You can save money by accepting a visible pipe in an unfinished section. Or by hiring a separate finish carpenter after the install.
Grants and warranties that cover Ontario mitigation
Ontario has more cost help than most provinces. Use it.
Tarion warranty (the big one)
This is the most important piece for any Ontario homeowner in a newer build.
Ontario is the only Canadian province with statutory radon coverage in its new home warranty.
- Bought from a registered builder
- Agreement of Purchase and Sale signed on or after February 1, 2021
- Currently inside the 7-year Tarion warranty term
Then your builder is legally on the hook for mitigation if a certified test reads at or above 200 Bq/m³. The warranty pays up to $50,000 of mitigation work.
That covers the actual cost in essentially every case.
We walk Ontario homeowners through the Tarion warranty claim process for free. It’s part of what we do for test customers.
Lungs Matter Grant
The Canadian Lung Association runs a grant program called Lungs Matter that covers up to $1,500 of mitigation costs for income-eligible homeowners.
The application is short. You need:
- A confirmed high radon test (≥200 Bq/m³)
- Proof of household income under the program threshold
- An installer quote
The grant pays directly to the installer in most cases. It stacks with no other federal program (the Canada Greener Homes Grant closed in February 2024). Worth a 10-minute application before you spend out of pocket.
Take Action on Radon free test kit programs
Some Ontario municipalities partner with Take Action on Radon to distribute free or subsidized test kits each fall.
These programs cover the test, not the mitigation. But they’re how a lot of Ontario homeowners discover they need mitigation in the first place, for free.
Real estate negotiations
If you’re buying a home and the inspection turns up high radon, the cost often becomes a credit at closing. The seller pays through a price reduction. Or installs the system before the deal closes.
Both work. Both cost the buyer nothing out of pocket.
DIY radon mitigation in Ontario: what’s allowed, what’s smart
There’s no Ontario law that requires a certified installer for residential radon mitigation. You can legally do the work yourself.
That doesn’t make it a good idea.
What you can DIY safely
A few tasks are well within reach for a handy homeowner:
- Seal visible slab cracks. A tube of polyurethane caulk closes minor cracks and slows radon entry. $15 in materials.
- Replace a sump pit cover with a sealed one. $30 part, 20-minute job. Cuts a major entry point.
- Swap a failed fan on an existing system. Cut power, unclamp the rubber couplings, slide the old fan out, slide the new one in. 30 minutes.
- Upgrade to a higher-CFM fan if your post-test was borderline. Same job as a swap. Match brand and pipe size.
What you should hire out
Almost everything else:
- Designing a full mitigation system from scratch. Sizing the suction point, picking the fan, routing the pipe, finding entry points. Get this wrong and your radon stays high while you assume it’s fixed.
- Drilling through a structural slab. You can hit rebar, hydronic lines, or post-tension cables.
- Crawl space membranes. Specialized work. A leaking membrane does nothing.
- Anything tied to a Tarion claim. Tarion requires a C-NRPP certified installer. DIY work voids the warranty path entirely.
A DIY full system saves $1,500 to $2,000 in labour. It costs you the verification that the work actually moved your radon number. And it can void your home insurance and Tarion warranty.
For the same logic we’d use on DIY electrical or DIY structural work: stick to small tasks. Hire out the rest.
What an Ontario mitigation install looks like
Most jobs run 4 to 6 hours, start to finish. The full sequence:
- Site visit. 30 minutes. Installer confirms foundation type, pipe route, fan size. Firm quote within 24 hours.
- Install day. Drill suction point, excavate small pit under slab, seal and run pipe, mount fan outside the home, cap above roofline, walk you through the manometer.
- Post-mitigation test. New radon test 30 to 90 days after install. Confirms the system actually dropped your number. A reputable installer pays for this test.
Power use is about 60 watts continuous. Adds $5 to $10 a month to your hydro bill. A properly installed exterior fan is quieter than a dishwasher.
A good system drops indoor radon by 80 to 99 percent.
We’ve covered the full install timeline in our Canada-wide mitigation guide if you want the deeper version.
How to choose an Ontario mitigator without overpaying
Four filters worth applying:
1. C-NRPP CRMT certification. The Canadian National Radon Proficiency Program issues two credentials.
2. Published pricing. Most Ontario radon companies hide their numbers behind a quote form. We don’t. If three or more companies on your shortlist refuse to share a starting price, that’s a yellow flag.
3. Written post-mitigation verification. A real workmanship warranty includes a follow-up test, paid by the installer, that confirms radon dropped below the guideline. If it’s not in the contract, it’s not real.
4. Tarion awareness. If your home qualifies, an installer who knows the warranty path is worth more than one who doesn’t. Many Ontario homeowners pay out of pocket for mitigation their builder was legally on the hook for, just because nobody told them.
For more on the Ontario testing side before you commit to mitigation, see our Ontario radon overview. The Government of Canada also publishes a plain-English radon overview worth reading before any spend.
Where Breathe Radon Free fits
We’re an Ontario-based testing service, owner-led, based in Guelph and serving the Greater Toronto Area plus surrounding Southern Ontario. We publish our prices. We follow Health Canada’s testing protocols on every job. And we tell you when you don’t need us.
Our published pricing:
- Residential test: $99 flat. 3 to 7 days, written report.
- Real estate transaction test: $399. Faster turnaround for closing timelines.
- Long-term test: $299. 91-day alpha track for ongoing residential.
- Mitigation: $2,800 to $3,800. Full system, post-mitigation verification, 5-year workmanship warranty.
- Tarion claim help: free for test customers.
If your test reads under 200 Bq/m³, we’ll tell you. We don’t sell mitigation to homes that don’t need it.
See full pricing and book a test. Or request a mitigation quote.
Frequently asked questions
Is radon mitigation cost the same across Ontario?
Mostly yes. The GTA, Hamilton, Kitchener-Waterloo, Guelph, London, and Ottawa all run in the $2,800 to $3,800 range for standard single-family homes. Rural areas and far-northern Ontario see a small travel surcharge from out-of-region installers. Toronto condos have higher mitigation costs because of permit and board considerations.
Can I deduct radon mitigation on my taxes?
Not directly as a personal medical expense in most cases. The Canada Greener Homes Grant covered radon work but closed in February 2024.
The Lungs Matter Grant is the main current cost-help program at the federal level.
How long until my mitigation system pays for itself?
It doesn’t, in dollar terms. Mitigation is a health spend, not an ROI spend. The Canadian Cancer Society calls radon the leading cause of lung cancer in Canadians who’ve never smoked.
For resale, a documented active mitigation system with a low post-test is a positive disclosure that removes radon as a deal-killer.
Will the price change if I have a finished basement?
A bit. A finished basement adds maybe $200 to $500 if the pipe needs to go through a closet or a chase. More if you want the pipe boxed in matching trim. The drill point itself is usually accessible behind a utility room or mechanical closet, so the slab work doesn’t change.
What if I get a quote that’s way under $2,800?
Be careful. Below $2,500 is rare for a real C-NRPP CRMT install with a verification test included.
Cheap quotes often skip the verification test, use undersized fans, or come from non-certified handymen. Ask whether the post-mitigation test is included in writing. If it isn’t, the price isn’t real.
Do mitigation systems need maintenance?
Very little. The pipe is permanent. The fan lasts 10 to 15 years and costs $200 to $500 to replace.
Check the manometer reading every few months. If the needle drops or the system gets noticeably louder, the fan may be failing. A re-test every 2 years confirms the system is still doing its job.
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Authored by the Breathe Radon Free Team. Every claim is backed by a primary source. Full bibliography at /sources.
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