Radon Map by Address and Postal Code

The RadonTest.ca Canada Radon Map lets you look up measured radon by city, census division or postal-code prefix, free and without signing up. It is built from 69,478 long-term radon tests collected between 2009-2024 — the largest residential radon dataset in Canada. Nationally, 17.8% of Canadian homes tested at or above Health Canada’s 200 Bq/m³ action guideline, with a typical (geometric mean) level of 84.7 Bq/m³.

Look up your area

Open the Canada Radon Map → Type a city, town or postal code into the search box, or tap any area on the map. You can switch between Health Canada’s 200 Bq/m³ guideline, the WHO’s 100 Bq/m³ reference level and the US EPA’s 148 Bq/m³ action level.

The underlying survey data is public; the RadonTest.ca Canada Radon Map is the free tool that makes it searchable — by province, city and postal code, in English and French, no signup.

What the map shows at each level of detail

• Province or territory — the headline rate for the 11 provinces and territories with a 2024 figure, shown below. The Northwest Territories and Nunavut are not separately reported in the 2024 survey; the map shows Health Canada’s 2009–11 result for those.
• Census division — 190 measured areas, roughly county-sized. This is the most useful level for most people.
• City and metro — 47 named cities and metro areas.
• Postal prefix (FSA) — for 429 postal areas with enough historical testing, the 2009–11 result at postal-prefix level, always labelled with its survey and year.
• Ground uranium — NRCan’s airborne equivalent-uranium reading for the ground beneath your area (GSC Open File 7402), which is what radon decays from.

Radon by province and territory

Provinces with few tests (Newfoundland and Labrador: 159; Prince Edward Island: 146) carry a wider margin of uncertainty — treat those percentages as indicative rather than precise.

Radon maps by province and city

• Nova Scotia radon map — 35.4%
• Ontario radon map — 15.8%
• Ottawa radon map — 17.0%
• Calgary radon map — 15.5%
• Montreal radon map — 17.4%
• Manitoba radon map — 43.6%
• Toronto radon map — 4.5%
• Carte du radon au Québec
• Carte radon Montréal
• Carte radon Ville de Québec
• Carte radon Sherbrooke
• Carte radon Gatineau
• Radon par code postal
• Carte du radon au Canada

The same area at three different thresholds

Canada’s action guideline is 200 Bq/m³. The World Health Organization uses a stricter 100 Bq/m³ reference level, and the US EPA acts at 148 Bq/m³ (4 pCi/L). Measured against each, RadonTest.ca’s Canada data reads:

No level of radon is completely risk-free — the risk rises with exposure, which is why the WHO line sits lower than Canada’s. Health Canada recommends acting within a year above 200 Bq/m³, sooner at higher levels.

Why this differs from older Health Canada figures

Health Canada’s 2009–11 national survey put Canada at about 11.3% of homes at or above 200 Bq/m³, from 13,814 valid tests (2009–11 figures as re-tabulated by the 2024 survey team), with a typical level near 55 Bq/m³. This page uses the 2024 Cross-Canada Survey of Radon — 69,478 long-term tests, the largest residential radon dataset in Canada — which puts Canada at 17.8% from 69,478 tests, typical level 84.7 Bq/m³.

Two things differ. First, the sampling: the 2009–11 survey recruited by random digit dialling across 121 health regions and deliberately over-sampled sparsely populated regions for geographic coverage, while the 2024 dataset aggregates long-term tests from homes whose occupants chose to test — which skews toward older housing, ground-contact basements and areas where radon is already a known concern. Second, the weighting: the 2009–11 figures quoted above are the raw, unweighted results. Because that survey deliberately over-sampled some regions, Health Canada also published population-weighted estimates, and its headline national result is 6.9%; the 11.3% raw figure comes from the 2024 survey team’s re-tabulation of the same dataset. None of these numbers is wrong — they answer different questions. For a population-representative estimate of Canadian housing, Health Canada’s weighted 6.9% is the right figure. For the largest body of actual measured results, use this page. Both are shown on the Canada Radon Map, and both can be switched between on the RadonTest.ca map. Full detail on methodology and sources.

A map cannot test your home

Every figure on the RadonTest.ca Canada radon map is an area figure. Two identical houses on the same street in your area can test very differently, because radon depends on your foundation, your soil, your ventilation and how you live in the house. The map tells you the odds. Only a long-term test tells you your number.

Health Canada recommends a long-term test of at least 91 days, and you can start it any time of year. Ideally at least 91 of those days fall in the heating season (roughly October to April), and there is a simple rule for when they don’t: if your result comes back below 200 Bq/m³ on a mostly-summer test, Health Canada suggests re-testing next heating season, because a summer test can read low. If it comes back above 200, Health Canada says no re-test is needed — act on it. Order a 91-day radon test kit for your home →

What to do if your result is above 200 Bq/m³

Health Canada recommends taking corrective action within a year above 200 Bq/m³, and sooner the higher the reading. Most Canadian homes are fixed with sub-slab depressurisation — a pipe running from beneath the foundation slab to a fan that vents above the roofline, which, when properly installed, reduces levels by more than 80% in most homes (Health Canada); results vary by house. In homes built under recent provincial codes, a capped radon rough-in should already be under the slab, which usually reduces the job to connecting a fan to pipe that is already there.

Work should be done by a professional certified through the Canadian National Radon Proficiency Program (C-NRPP), and the home should be re-tested afterwards to confirm the fix worked. You can also look up radon by address or postal code anywhere in Canada on the RadonTest.ca map.

Radon map by address — questions

Can I get a radon reading for my exact address?

No, and neither can anyone else. Radon is measured inside individual buildings. Two identical homes next door to each other can differ by a factor of ten. Any service claiming an address-level radon "result" is producing a geological model, not a measurement.

Is there a free radon map by postal code in Canada?

Yes. The RadonTest.ca Canada Radon Map is free and needs no signup. It covers 69,478 measured tests across 190 census divisions, and shows a postal-prefix (FSA) reading for 429 postal areas.

What radon level is a problem in Canada?

Health Canada’s action guideline is 200 Bq/m³, with mitigation recommended within a year above that and sooner at higher levels. The WHO reference level is 100 Bq/m³ and the US EPA acts at 148 Bq/m³. No level of radon is completely risk-free. Nationally 42% of Canadian homes are above the WHO level and 17.8% above Canada’s.

Recommended citation: Radon Map by Address and Postal Code, RadonTest.ca, 2026. Data: 2024 Cross-Canada Survey of Radon (v1.1 (CCSR.24.1.1), ISSN 2818-8195). https://radontest.ca/pages/radon-map-by-address Data licensed CC BY 4.0 — attribution required: “RadonTest.ca Canada Radon Map”.