Every public radon map for Canada, what each measures, how Nova Scotia's compares with other countries', and why none can tell you your home's level.
Photo: Carl Young, CC BY-SA 4.0, cropped, via Wikimedia Commons.
30
cm of groundDepth of ground behind the national airborne uranium map, built from more than 370 surveys flown from 1969 to 2011. It shows where radon is more likely, not the level in any building.
Canada has several kinds of radon map, and each one measures something different. Some show tested homes, some show the ground, and some show who has heard of radon. None of them can tell you the radon level in your home. The 2024 survey says no area of Canada is radon free. See the survey’s figures for your area, with their source.
Radon maps and data in Canada come in five kinds:
On a measured map or a regional summary, the colour depends on how much data sits under it. In the 2024 Cross-Canada Radon Survey (Version 1.1), 245 of 293 census divisions (83.6%) had at least one home at or above 200 Bq/m³. Only 171 census divisions had 25 or more readings. Nunavut has no indoor test results, and thirteen cities need more testing before they can be reported. Get every census division figure, with its sample.
Health Canada lists these public radon maps, and each one draws on different data:
Health Canada’s list also includes one commercial mapping product sold for a fee. See how many homes are high, and where.
Nova Scotia’s radon potential model layers bedrock geology, surficial geology, airborne uranium and measured indoor radon. It covers the whole province, and its community statistics draw on over 4,500 buildings. The province publishes its methods and GIS data, and expects about 36.8% of homes to exceed 200 Bq/m³ and says no region is free of homes over that level.
The European indoor radon map, updated in November 2024, uses 10 km cells of ground-floor rooms. It also publishes a second map of the number of measurements in each cell. No Canadian public map publishes this count. See why geology alone does not set a home’s level.
A lookup by postal code gives you a figure for an area, not a reading from your home. The C-NRPP map groups results by the first three characters of a postal code. It shows an area only once at least ten properties there have been tested.
The number for an area can also change with the method behind it. The 2024 survey weights its results, and weighting raised Prince George’s average by 18% and lowered Kelowna’s by 15.4%. Two maps built from the same tests can show different averages for the same place. Read why a map is not a condition report in a sale.
Every survey behind these maps tells you to test your own home. High readings turn up even in cities with low averages, such as Toronto and Vancouver.
1,013
Bq/m³Highest reading the 2024 survey recorded in Toronto, a city with a weighted average of 43.0 Bq/m³. In Vancouver, average 17.1, the highest was 624 Bq/m³.
The 2024 survey calls the instinct to relax at a low average optimism bias. It says its results should not decide whether a home is tested. The US EPA says its 1993 Map of Radon Zones should not decide that either. Health Canada says radon is found in every building in Canada at some level. See how to test your own home.