Radon Map of Canada: Province-by-Province Risk Breakdown
New Brunswick. Manitoba. Saskatchewan.
Three provinces where roughly 1 in 5 homes test above Health Canada’s 200 Bq/m³ action level.
Most Canadians never look at a radon map. They figure it’s a Western problem, or a Northern problem, or somebody else’s problem. The data tells a different story.
This post walks through real province-by-province numbers from Health Canada’s Cross-Canada Survey. We’ll show you which provinces run hot, which run cooler, and why every province has a problem in some pocket.
The short version:
- Health Canada’s nationwide survey tested almost 14,000 homes across every province and territory
- New Brunswick, Manitoba, and Saskatchewan top the list for share of homes above 200 Bq/m³
- Ontario averages around 92 Bq/m³, but Kingston, Ottawa, and Guelph all run far higher
- Even the lowest-risk provinces have neighbourhoods that test above guideline
- The map gives you the odds for your area. Only a test gives you your home’s number.
- A DIY long-term kit runs $35 to $60. A pro test runs $99.
Where the radon map data comes from
The single best source is Health Canada’s Cross-Canada Residential Radon Survey.
It ran from 2009 to 2011 and placed long-term tests in almost 14,000 homes. Each home got a 91-day alpha-track test through the winter heating season. That’s the most conservative reading you can get.
The survey covered every province and territory. Results were broken down by health region, then rolled up by province.
A second source is CAREX Canada, a cancer exposure tracking project run out of Simon Fraser University.
A third source is Take Action on Radon, the national outreach program run by CARST.
A fourth source is Evict Radon, a research-led volunteer program with over 60,000 Canadian homes in its database.
When all four sources agree, the number is solid. When they disagree, trust the most recent winter long-term data.
The province-by-province ranking
Here’s the picture from the Cross-Canada Survey, sorted by share of homes above 200 Bq/m³.
| Province or Territory | % of homes above 200 Bq/m³ | Notes |
|---|---|---|
| New Brunswick | ~21% | Highest in Canada. Granite-rich bedrock across most of the province. |
| Yukon | ~20% | Small sample, but very high readings throughout. |
| Manitoba | ~19% | High across the southern half. Winnipeg averages around 105 Bq/m³. |
| Saskatchewan | ~16% | Regina and Saskatoon both run above the national average. |
| Northwest Territories | ~15% | Yellowknife and surrounds, on Shield bedrock. |
| PEI | ~12% | High for a small province. Sedimentary rock with uranium pockets. |
| Quebec | ~10% | High in the Outaouais and Eastern Townships. Lower in the St. Lawrence valley. |
| Ontario | ~8% | Average around 92 Bq/m³. Kingston, Ottawa, and Guelph run far above. |
| Alberta | ~7% | Calgary, Lethbridge, and southern Alberta run higher than the average. |
| Nova Scotia | ~7% | Granite pockets in Halifax, the South Shore, and Cape Breton. |
| British Columbia | ~6% | Low in the Lower Mainland. High in the Kootenays and Okanagan. |
| Newfoundland and Labrador | ~5% | Lowest in Canada. Older sedimentary rock holds less uranium. |
| Nunavut | small sample | Most homes lack basements. Lower exposure overall. |
The cross-Canada average sits around 84 Bq/m³.
Why the highest-risk provinces test so high
Three provinces top the list. The reason is the same in each one.
New Brunswick
New Brunswick sits on a slab of uranium-bearing granite. The bedrock is close to the surface across most of the province. Soil is thin.
Gas paths from the ground to the basement are short and direct. Health Canada’s data shows roughly 1 in 5 New Brunswick homes above guideline.
Manitoba
Manitoba has the highest big-city radon level in Canada south of the Shield. Winnipeg sits on permeable sediments that let soil gas rise easily.
Most basements are below grade. Winter cold makes the stack effect strong. The Manitoba Lung Association has flagged radon as a major public health issue for years.
Saskatchewan
Saskatchewan runs hot for the same reasons. The provincial average is over 100 Bq/m³.
Regina, Saskatoon, and the small towns around them all test high. Granite below, permeable soil above, and cold winters that drive negative pressure into the basement.
The Atlantic provinces follow a slightly different pattern. New Brunswick is high overall, but PEI and Nova Scotia have pocket high-radon areas tied to specific geology. The South Shore of Nova Scotia and the central PEI granite belt both test above the national average.
Why even low-risk provinces have high-risk homes
This is the part most maps miss.
British Columbia is the second-lowest-risk province in the Cross-Canada Survey. Most BC homes test under 50 Bq/m³.
But the Kootenays and the southern interior are different. Cranbrook, Castlegar, and Nelson all sit on Shield-like rock. Test results in those towns sometimes top Yukon-level averages.
Newfoundland and Labrador has the lowest provincial average. It also has Labrador City, which sits on iron-ore-rich Shield rock and tests very high.
Even Ontario, which averages a moderate 92 Bq/m³, has Kingston at 25 percent above guideline.
The lesson is simple. A province-level map gives you the rough odds. It cannot tell you about your street.
Radon levels vary by a factor of 10 between neighbouring homes on the same street. Same builder, same year, same soil, different readings. A map can’t see foundation cracks, sump pits, or how hard your furnace pulls air through the slab.
The Ontario picture
Since we work here, we know this province best.
Ontario sits on a mix of two rock systems. The Canadian Shield covers the north and east. Glacial deposits and limestone cover the south.
Provincial average: about 92 Bq/m³.
The real story is the regional spread.
- Kingston and eastern Ontario: 25 percent of homes above guideline
- Ottawa Valley: Canada’s highest big-city average
- Wellington County (Guelph area): about 10 percent above guideline
- Hamilton-Niagara: about 10 percent above guideline
- Kitchener-Waterloo: 8 to 10 percent
- GTA (Toronto): around 3 to 5 percent
For a deeper view, see our radon map of Ontario. It breaks the province down by region with the actual numbers. The full picture on radon itself is in our Ontario radon guide.
What action level Canada uses (and why it matters)
The Canadian guideline is 200 Bq/m³.
The US action level is 148 Bq/m³ (4 pCi/L). The World Health Organization recommends 100 Bq/m³ as a reference level.
The numbers all measure the same thing. Just different cut-offs.
Canada’s higher number doesn’t mean Canadian homes are safer. It means the action threshold here is more permissive.
If your home reads between 100 and 200 Bq/m³, you’re below the Canadian action level. You’re above the WHO reference. Many Canadian experts treat 100 Bq/m³ as a “think about it” line and 200 as a “fix it” line.
What the map should make you do
Three steps. In order.
1. Find your province on the table above. Read the percent of homes above guideline. That’s your starting odds.
2. Test your own home. A long-term kit from Canadian Tire runs $35 to $60. A pro test runs $99.
The kit takes 91 days through the winter. The pro test takes 3 to 7 days.
3. Act on the number. Under 100 Bq/m³, retest in 5 years. Between 100 and 200, do a confirmatory long-term test.
Above 200, plan to mitigate within 12 months. Above 600, within 6 months.
If you need to mitigate, the standard fix is sub-slab depressurization. It works in 80 to 99 percent of Canadian homes. A typical Ontario install runs $2,800 to $3,800.
For more on placement and timing, Health Canada’s guide for residential radon measurements is plain English and free.
DIY map check vs hiring a pro
You can do most of this yourself. Some steps are worth paying for.
| Step | DIY is fine | Hire a pro |
|---|---|---|
| Look up your province in the Cross-Canada Survey | Yes, free at canada.ca | Not needed |
| Read the city-by-city Take Action on Radon results | Yes, free at takeactiononradon.ca | Not needed |
| Buy a long-term test kit | Yes, $35 to $60 at Canadian Tire | Only for a real estate timeline or a Tarion claim |
| Place the kit | Yes, follow the placement card | If your home is unusual (multiple slabs, large footprint) |
| Read the lab result | Yes, the number arrives in Bq/m³ | If you’re between 100 and 200 and unsure what to do |
| Run a 3 to 7 day test for a real estate deal | No, timing-sensitive | Yes, $99 short-term test or $399 real estate test |
| Design and install a mitigation system | No | Yes, sizing and venting need to be right |
The honest answer: for a non-urgent first test, a DIY kit is the right call. Don’t pay for a pro test until you have a number.
We’d rather you spend $40 with a good kit than $99 with us if you don’t need us.
When to retest
Radon levels don’t stay frozen. Your number can move over the years.
Retest if any of these happen:
- You finish a basement
- You install a new furnace or HVAC system
- You add a sump pump or change the sump cover
- You seal or replace a foundation slab
- You add a basement bedroom (especially for a child)
- 5 years have passed since your last test
The Canadian Cancer Society’s radon page covers the long-term health stakes if you want the bigger picture.
For a deeper dive into what changes radon levels inside the house, our FAQ page covers the most common ones in plain English.
Where Breathe Radon Free fits
We’re an Ontario-based testing service, owner-led, based in Guelph. We serve the Greater Toronto Area plus surrounding Southern Ontario.
We publish our prices. We tell you when you don’t need us.
- 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 days, the most accurate residential measure.
- Mitigation: $2,800 to $3,800. Full system, post-mitigation verification, 5-year workmanship warranty.
- Tarion claim help: free for test customers.
If you live outside our service area, the Health Canada radon overview is the right starting point.
Book a $99 radon test in 60 seconds.
Frequently asked questions
Which Canadian province has the worst radon problem?
New Brunswick has the highest share of homes above the 200 Bq/m³ Health Canada guideline at about 21 percent. Manitoba and Saskatchewan are close behind. Yukon also runs very high, though the sample size is smaller.
Which province has the lowest radon levels?
Newfoundland and Labrador had the lowest average in the Cross-Canada Survey. British Columbia is the second-lowest, with most coastal homes testing well below the guideline. But both provinces have hot spots, like Labrador City and the BC Kootenays.
Is there an official Canada radon map?
Health Canada publishes the Cross-Canada Survey results, but there isn’t a single official heat map updated in real time. The best sources together are the Cross-Canada Survey, CAREX Canada’s radon profile, Take Action on Radon’s city-by-city challenge results, and the Evict Radon study database.
If my province has low average radon, do I still need to test?
Yes. Province-level averages hide neighbourhood-level differences. Radon varies by a factor of 10 between homes on the same street, so the map only gives you the odds. Only a test gives you your home’s number.
How much does a radon test cost in Canada?
A long-term DIY kit from Canadian Tire or a Take Action on Radon program runs $35 to $60. A short-term pro test runs $99 to $200 depending on the provider. A real estate transaction test runs $300 to $400 for faster turnaround.
Get a $99 radon test for your home →
Authored by the Breathe Radon Free Team. Every claim is backed by a primary source. Full bibliography at /sources.
Ready to test your home?
Get a quote in 60 seconds. Published prices, no sales follow-up.