Calgary radon map and risk guide

What does the map of Calgary show?

It shows the area this page covers, and deliberately nothing more. The four quadrants and the surrounding towns are drawn in one neutral colour because no published dataset ranks Calgary's quadrants or neighbourhoods by radon, and we will not shade an area on a guess. The figures in the box are for the Calgary area as a whole.

What does the research say about radon in Calgary?

That a substantial share of homes are above the guideline, and that the larger, more recent surveys report the higher shares. A University of Calgary-led study published in 2017 tested 2,382 homes in Calgary and area and found about 1 in 8 at 200 Bq/m³ or moresource. In that study 47.6% of homes were at 100 Bq/m³ or higher, and the average was 126 Bq/m³source. The 2024 survey quoted above found a larger proportion over the guideline in the Calgary area, close to the national picture: about 1 in 5 residential buildings across Canada (17.8%) at or above 200 Bq/m³source.

The numbers differ because the studies differ: sample size, the years covered, which floor was tested and how homes were recruited. Read together they point the same way. Roughly one home in six to eight in and around Calgary has tested above the guideline in the larger studies, and a far bigger group sits between 100 and 200 Bq/m³.

How should I read a radon statistic?

By checking four things before comparing one figure with another.

• The threshold. "At or above 200 Bq/m³" and "at or above 100 Bq/m³" describe very different groups of homes, and reports quote both.
• The kind of average. A plain average is pulled upward by a few very high homes. Some reports use other kinds of average that sit lower for the same data, so two averages are comparable only when they were calculated the same way.
• The floor tested. A basement reading and a main-floor reading from one house are not the same number. Some surveys adjust their results to a common floor and some do not.
• The sample. Eighty-six homes and two thousand homes do not carry the same weight, and people who volunteer for a study are not a random draw of the city.

None of this weakens the main conclusion. It explains why the percentages in the table are not identical, and why we quote each with its source and year and do not merge them into one headline number.

Which parts of Calgary have higher radon?

Nobody has published data that answers this reliably, and we would be inventing it if we named quadrants or communities. What the research does support is a pattern by type of house, not by postal code. In the 2017 study, homes built in 1992 or later averaged 31.5% more radon than older onessource. The larger 2019 study linked higher levels with recent construction, bigger floor area, fewer storeys, taller ceilings and windows that are opened lesssource.

Those traits are more common in newer suburbs than in older inner-city streets, which may be why people report that "new communities are worse". The research supports saying that newer houses have tended to test higher. It does not support telling the owner of an older bungalow that the house is fine, since homes of every age appeared above the guideline. A 2021 comparison found Canadian houses from the 2010s and 2020s averaging 131 Bq/m³ against 28 Bq/m³ in Swedensource, which points at how houses are built as much as at the ground beneath them.

What about the towns around Calgary?

The same caution applies, with one area that researchers have singled out. Dr. Aaron Goodarzi of the University of Calgary has described the Okotoks and Foothills area as among the most radon-exposed regions observedsource. A national study published in 2024, drawing on 42,051 homes, found average radon as much as 31.2% greater in rural, lower population density communities than in urban equivalentssource, and linked a majority of that effect to proximity to drilled groundwater wells, not to drinking or using the watersource.

The 2017 study drew its out-of-town homes from communities including Airdrie, Cochrane, Okotoks and Chestermere, so the "Calgary and area" figures already contain them. Published town-level figures are few and differ in kind, so each town has its own page that says exactly what exists: Airdrie, Cochrane, Okotoks and Chestermere.

Why can't a map tell me my home's level?

Because the level is set under and inside one building. Health Canada notes that radon varies from one house to another even when the houses are of similar design and stand next door to each othersource. The gas comes in through cracks in the foundation floor and walls, construction joints, gaps around service pipes, floor drains and sumps, pulled by indoor air pressure that is usually lower than the pressure in the soilsource.

Every item in that list is particular to a house. The gravel under one slab is loose and under the next it is packed. One basement has a sealed sump and its neighbour's is open. One family keeps the bedroom windows cracked all winter and another never does. A regional percentage averages all of this away, which is exactly what makes it a poor predictor for a single address.

Can I look up radon by address?

Not in a way that deserves trust. Some websites return a value or a colour for a street address. Behind it is an estimate built from nearby results or from geology, not a measurement of that building, and neighbouring houses can differ widely. Treat an address lookup as a statement about likelihood in the district. A seller's or previous owner's test report for the actual house is far more useful, and a new test in the rooms you will live in is better still.

Which public maps and dashboards can I use?

Two are worth knowing, and both come with limits stated by their publishers.

• Health Canada's radon map link now leads to the 2024 Cross-Canada Survey, whose interactive dashboard filters results by region, house type and community typesource. Its figures are adjusted as if every participant had tested on the same floor, and it describes regions, not addresses.
• Health Canada's 2012 survey reported 8.1% of the 86 homes sampled in the Calgary health region above 200 Bq/m³, and Health Canada states that those results should not be used to determine radon risk potential or whether to test a homesource. With so few homes it is a historical reference only.

A low-looking region on any of these is not a reason to skip testing. Health Canada's recommendation is that every home be tested, regardless of location or building typesource.

What will your own results add?

Measurements from homes we test and mitigate, grouped by area and stripped of anything that identifies a household. We will publish a figure for an area only when it rests on enough tests to mean something, and we will state the number of tests beside it. Until then this section stays empty by design.

What would a real neighbourhood map need?

More than a few results per community, collected the same way. To colour an area honestly, the tests behind it would have to be long-term, taken on comparable floors and numerous enough that one unusual house cannot move the figure. The results would have to be published as counts and ranges, so a reader can see how much data stands behind a colour. And every household would have to stay unidentifiable, which rules out showing areas where only a handful of homes have been tested. That is the standard we will hold our own data to before any of it appears on this page.

Can I cite or reuse this page?

Yes. Realtors, home inspectors, community associations and journalists are welcome to link to it and to quote it with attribution. For any figure, please cite the original study named in the table and under Sources, with its year, since those are the primary sources and this page is a summary of them. If you are preparing an article or a newsletter and need the reference for a number, email us and we will point you to it.

How was this page put together?

From published sources only: Health Canada, the 2024 Cross-Canada Survey, peer-reviewed papers from the University of Calgary group, and attributed statements by its lead researcher. Each is linked under Sources with its year. Percentages are quoted as published and not recalculated. Where studies disagree we show each figure with its date instead of choosing one. The map carries no risk colours, and no number on this page describes a neighbourhood. We review the page each quarter and when a major study appears; the date at the top changes only when the content does.

What should I do next?

Test, whatever the map suggests. Health Canada's guideline is 200 Bq/m³ as an annual averagesource, and only a long-term measurement in your home can be set against it. If you have not tested, see radon testing in Calgary or the do-it-yourself route on radon test kits. If you already have a long-term result above the guideline, radon mitigation in Calgary explains the assessment and the system, and the form on this page starts the conversation.