What is radon?
A radioactive gas released when uranium in soil and rock breaks down. It seeps into homes through foundation cracks, sumps and gaps around pipes.
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Radon Action MonthRadon in homes
Radon in homes
near you?
Explore radon levels in your area using national survey data.
Radon across Canada
Selected postal area:
Tested homes at or above 200 Bq/m³
Under 5%
5–10%
10–20%
20–30%
30%+
No homes tested in this postal area
Explore radon levels in your area
Enter your postal code above or select a region on the map to view local radon data.
Results by province and territory
| Province / territory | Homes tested | Median, Bq/m³ | At or above 100 Bq/m³ | At or above 200 Bq/m³ |
|---|---|---|---|---|
| Alberta | 1,132 | 71 | 33% | 6.6% |
| British Columbia | 1,817 | 23 | 18% | 7.9% |
| Manitoba | 1,183 | 101 | 51% | 24% |
| New Brunswick | 831 | 84 | 45% | 25% |
| Newfoundland and Labrador | 713 | 23 | 17% | 5.9% |
| Northwest Territories | 185 | 37 | 23% | 5.4% |
| Nova Scotia | 592 | 28 | 21% | 8.8% |
| Nunavut | 78 | 8 | 0% | 0% |
| Ontario | 3,954 | 40 | 25% | 8.2% |
| Prince Edward Island | 113 | 20 | 12% | 3.5% |
| Quebec | 1,785 | 32 | 23% | 10% |
| Saskatchewan | 1,206 | 97 | 49% | 16% |
| Yukon | 225 | 90 | 44% | 20% |
| All of Canada | 13,814 | 47 | 30% | 11% |
What the numbers mean
Radon is measured in becquerels per cubic metre (Bq/m³). No level is completely safe — the lower, the better.
Under 100
Below the WHO reference level
The World Health Organization recommends keeping homes below 100 Bq/m³ where possible.
100 – 199
Above the WHO reference level
Below Canada's guideline, but reducing it still lowers your long-term risk.
200 and above
Health Canada guideline — take action
Health Canada advises reducing the level. The higher it is, the sooner it should be fixed.
About radon
Radon is the leading cause of lung cancer in people who have never smoked. You can't see, smell or taste it — testing is the only way to know.
Test for at least 3 months
Health Canada recommends a long-term test of 3 months or more, ideally in fall and winter, in the lowest level where you spend 4 or more hours a day.
Why monitor continuously
Radon rises and falls with weather, season and ventilation. A digital monitor shows the long-term average and how it changes after you fix it.
High levels can be fixed
The most common fix is sub-slab depressurization, which vents radon from under the house. Use a C-NRPP certified radon professional.
Data & method
Every figure on this page comes from public Government of Canada data. Here is what we used and how.
Sources
Cross-Canada Survey of Radon Concentrations in Homes
Health Canada, 2009–2011. 13,814 long-term tests in all provinces and territories. Open Government Licence – Canada.
2021 Census boundary files — provinces and forward sortation areas
Statistics Canada. Simplified for the web. Open Government Licence – Canada.
2024 Cross-Canada Radon Survey
Evict Radon National Study (University of Calgary, with Health Canada and partners). Quoted for the national figure only.
Contains information licensed under the Open Government Licence – Canada. This page is made by Aranet and is not endorsed by the Government of Canada.
How the figures are calculated
- A postal area is the first 3 characters of a postal code (forward sortation area, FSA).
- Postal areas with at least 10 tests show their own result. Areas with fewer show the result of the health region their tests came from. Areas with no tests show the province on lookup and are hatched on the map.
- Shares are of tested homes. They are not weighted by population, so they differ from Health Canada's national estimate (6.9%).
- Readings below the detection limit (<15 Bq/m³) are counted as 7.5 Bq/m³ in averages.
- The survey is from 2009–2011. The 2024 national study found a higher share of homes above the guideline, so levels today are likely higher than shown.
- An area's result cannot predict the level in any single home. Health Canada recommends that every home be tested.
Your area is a starting point. Your home is the answer.
Two houses on the same street can have very different radon levels. Aranet Radon Plus measures your own home, day and night.
- Measures radon continuously and shows it on an easy-to-read e-paper display
- Also shows temperature and humidity
- Full history in the free Aranet Home app
- Readings in Bq/m³ or pCi/L
