It starts in the ground
Uranium in rock and glacial soil decays into radon gas. Southern Ontario’s glaciers spread Shield-derived debris everywhere, and black shales add more in places.
Read more
Radon testing & mitigation · Windsor to Brantford
Find out what’s in your basement air. Fix it if it’s high.
Radon is an invisible gas that seeps up from the ground into Ontario homes, and it’s the leading cause of lung cancer in people who have never smoked. We measure it the way Health Canada recommends, with an early reading in as little as 2 weeks, vent it outside when it’s high, and prove the fix worked.
- C-NRPP certified
- Early reading in 2 weeks, full result at 91 days
- Fixed prices, guaranteed results
Basement reading
412 Bq/m³
Above guideline
- Certified, insured, localC-NRPP certified professionals based in London.
- Health Canada protocolAn early reading at 2 weeks, then a 91-day test, accredited lab and written report.
- Systems built to standardDesigned and installed to CAN/CGSB-149.12.
- Results guaranteedBelow 200 Bq/m³ on retest, or we come back free.
Why it matters
The second leading cause of lung cancer is in the basement.
After smoking, radon is the biggest cause of lung cancer in Canada. It can’t be seen, smelled or felt, and it doesn’t care whether your house is old, new, expensive or modest. Two houses on the same street can test very differently.
The good news: radon is one of the most fixable health risks in a home. A long-term test tells you your level. If it’s high, a mitigation system typically cuts it by 90% or more in a single day of work.
1 in 8
Ontario homes at or above Health Canada’s guideline in the 2024 national survey
Cross-Canada Survey, 2024For people who smoke, the risk from radon is far higher, and the two together multiply. For non-smokers, radon is the number one cause of lung cancer.
What changed in 2007
Canada moved the line. Most homes never re-tested.
In June 2007, Health Canada cut its radon guideline from 800 to 200 Bq/m³, a 75% drop.
New research pooling residential studies from Europe and North America had linked lung cancer to radon at far lower levels than anyone thought. Overnight, homes that had “passed” were over the limit. Many of them still haven’t been re-tested, and many homeowners have never heard the guideline changed at all.
If your home was tested before 2007, or bought with a short test during a sale, it’s worth testing again.
Canada’s radon guideline
1988In 1988 Canada’s guideline for indoor radon was 800 becquerels per cubic metre. In June 2007 Health Canada lowered it to 200. Homes between 200 and 800, once considered acceptable, are now above the guideline.
Reclassified band: 200–800 Bq/m³
WHO reference level: 100
U.S. EPA action level: ≈148 (4 pCi/L)
A home that tested 600 Bq/m³ in 2005 was under the limit. Today Health Canada says to fix it within one year.
Radon, briefly
Where it comes from, how it gets in, and when it’s risky
Three things every Southern Ontario homeowner should know.
Your house pulls it in
Warm air rising through a heated home lowers pressure at the basement. Soil gas is drawn in through cracks, sumps, drains and the gap where walls meet the floor.
Read more
Risk = level × time
Radon harms over years, not days. It’s highest in winter and on the lowest floor, so basement bedrooms and home offices matter most.
Read more
How it works
Identify, measure, fix, verify
A clear process with no guesswork. You’ll know what we’re doing, why, and what it costs before we start.
1. Identify
Book, and we plan the right test
A short call to learn about your home: foundation, how you use the basement, any past results. We pick test locations by Health Canada’s protocol: the lowest level where someone spends four or more hours a day.
What we ask about
- Basement bedrooms, offices or suites
- Sumps, drains and crawlspaces
- Additions on different foundations
- Real estate or closing deadlines
2. Measure
An early reading at 2 weeks, the full result at 91 days
A certified technician places long-term alpha-track detectors where they’ll give a true reading: away from drafts, sumps and exterior walls, with a calibrated monitor beside them for the first 2 weeks. That gives you an early reading. You live normally, and after 91+ days we send the detectors to an accredited lab.
91 days minimum.
Radon swings hour to hour and season to season. Three months or more, through the heating season, gives a true annual average. An early reading at day 14 tells you sooner if it’s clearly high.
Radon swings hour to hour and season to season. Three months or more, through the heating season, gives a true annual average. An early reading at day 14 tells you sooner if it’s clearly high.
3. Understand
Your result, explained plainly
You get a written report with your average concentration, what it means against Health Canada’s guideline, and what (if anything) to do next. No pressure: about seven in eight Ontario homes come back below 200.
Health Canada’s timelines
- Under 200 Bq/m³: no action needed
- 200–600 Bq/m³: reduce within 2 years
- Over 600 Bq/m³: reduce within 1 year
4. Fix
A mitigation system designed for your house
If your level is high, we assess the foundation, run a sub-slab communication test and design an active soil depressurization system to CAN/CGSB-149.12. Most homes are done in a day, with a fixed price agreed up front.
Every install includes
- Sealed sump and major cracks
- Quiet, efficient fan outside living space
- Manometer so you can see it working
- Clean pipe route you approve first
5. Verify
Proof it worked
We confirm suction across the slab on install day, then you run a follow-up long-term test. If it isn’t under 200 Bq/m³, we come back and adjust the system at no cost.
After the install
- Short-term check after 24 hours of operation
- Long-term follow-up test
- Re-test every few years or after renovations
Already tested?
What does your number mean?
Enter your result in Bq/m³ or pCi/L (U.S. kits report in pCi/L). We’ll tell you what Health Canada recommends, in plain language.
- Under 200 Bq/m³: below the Canadian guideline
- 200–600 Bq/m³: reduce within 2 years
- Over 600 Bq/m³: reduce within 1 year
Enter a number to see what it means.
Health Canada’s guideline is 200 Bq/m³, based on a long-term test of at least three months.
Where we work
From Windsor to Brantford, town by town
Every area page explains the ground under it, the local housing, and the factors that matter there. No made-up risk scores, just what’s known and what to do.
Base map: Natural Earth (public domain). Thames and Detroit rivers traced approximately. Kitchener and Waterloo are drawn slightly apart. Hover or tap a town to open its page.
Who we help
Families, home buyers and builders
Homeowners and families
- Early reading at 2 weeks, 91-day result
- Clear report and advice
- Mitigation with guaranteed results
Buying or selling
- Testing that fits a closing date
- Written results for both parties
- Quotes for buyers and sellers
Builders and developers
- 2024 OBC rough-ins done right
- Post-occupancy testing programs
- Warranty callbacks handled for you
Are you a C-NRPP certified contractor?
Join our network and get steady, pre-qualified radon work across Southern Ontario.
Questions
Radon questions we hear every week
What is radon, and why does it matter?
Radon is a radioactive gas that forms naturally as uranium in soil and rock breaks down. It has no colour, smell or taste. Outdoors it dilutes to harmless levels, but it can build up indoors, especially in basements. Breathing it over years damages lung tissue: Health Canada calls radon the leading cause of lung cancer in people who have never smoked.
Is radon really a problem in Southern Ontario?
Yes. Radon isn’t limited to the Canadian Shield. Glacial soils across Southern Ontario carry uranium-bearing rock, and the 2024 Cross-Canada Survey found about 1 in 8 Ontario homes at or above Health Canada’s guideline. In Windsor-Essex, the local health unit’s 2015 to 2018 study found about 11% of homes tested above it.
How long does a radon test take?
Health Canada recommends a long-term test of at least three months (91 days), ideally between October and April. You don’t have to wait that long for a first answer: a calibrated monitor next to the detector gives you an early reading at 2 weeks. If it’s far above 200 Bq/m³, your 91-day result is very likely high too. How the early reading works.
How much does radon mitigation cost in Ontario?
Most single-family sub-slab depressurization systems in Canada cost roughly $2,000 to $3,500, with complex homes (several foundations, finished basements needing careful routing, crawlspaces) costing more. We give a fixed quote after a site assessment. See what drives the price.
Can I test my own home?
Yes. A do-it-yourself long-term kit from a C-NRPP listed supplier is a good option. A professional test adds correct placement, chain of custody, a lab-verified report you can use for a real estate deal or a Tarion claim, and an expert to explain the result.
Do new homes have radon?
They can, and Canadian research found newer homes have tended to test higher than older ones. Homes permitted under the 2024 Ontario Building Code include a soil gas barrier and a capped rough-in pipe, but that rough-in does nothing until a test shows it’s needed and a fan is added.
Book a test
One heating season to a real answer.
Most homes come back below the guideline, and then you’ll know for sure. If yours doesn’t, you’ll have a clear plan, a fixed price and a guarantee.
- Call-back within one business day
- Technician visit takes about 30 minutes
- Written lab report and a plain-language explanation
Prefer to talk? (226) 271-4667