A note before you read. This is general consumer information for Northwest Territories homeowners, buyers, sellers, landlords, and renters, drawn from publicly available Health Canada, Government of the Northwest Territories, NWT Legislative Assembly, and peer-reviewed sources. It is not medical, legal, or warranty advice. Radon results are reported against the Health Canada guideline of 200 Bq/m³; RadonTest.ca coordinates testing logistics and does not interpret individual results or provide health assessments.
Key facts: radon in the Northwest Territories at a glance
- The NWT has limited radon data, and that itself is the headline. Health Canada's Cross-Canada Survey found 5.4% of NWT homes above the 200 Bq/m³ guideline (from a small sample of 185 homes), while a 2024 national study placed a combined "Northern" region of the NWT and Yukon at about 1 in 5 (20.5%) above the guideline. The honest position: there isn't enough recent NWT-specific testing to state a reliable territorial rate — which is exactly why testing your own home matters.
- Radon is the number one cause of lung cancer in non-smokers and the second leading cause overall, after smoking.
- The geology cuts both ways. Parts of the NWT sit on uranium-bearing Canadian Shield bedrock with a long uranium-mining history; permafrost can trap radon underground, but thawing permafrost is expected to release more of it over time.
- The Health Canada guideline is 200 Bq/m³ (annual average). If your long-term result is above it, Health Canada recommends taking corrective action within one year — sooner the higher the level.
- The NWT has no new-home warranty that covers radon, no territorial radon grant, and no dedicated radon-awareness program. The NWT Legislative Assembly's own 2026 review confirmed there are "no territorial programs that explicitly support radon mitigation or testing."
- Testing takes a minimum of 91 days (a long-term test). Fixing a home typically costs around $2,700, and a system installs in about a day — though remote communities can cost more, and certified mitigators are scarce in the North.
How much radon is in NWT homes?
Radon is a naturally occurring radioactive gas with no colour, smell, or taste. It seeps up from the breakdown of uranium in soil and bedrock and accumulates indoors. Every NWT home has some radon; the difficulty in the Northwest Territories is that there is very little recent, territory-specific data on how much.
Here is what exists, kept straight:
- Health Canada's Cross-Canada Survey of Radon Concentrations in Homes (data collected 2009–2011, published 2012). Of 185 valid NWT results, 5.4% were at or above 200 Bq/m³ (4.9% in the 200–600 range and 0.5% above 600). That is a low figure relative to high-radon provinces — but the sample was small, and a low result from 185 homes more than a decade ago is a weak basis for concluding the territory is low-radon.
- The 2024 Evict Radon / University of Calgary national study. This academic survey reported a combined "Northern" region (NWT and Yukon together) at about 1 in 5 homes (20.5%) above the guideline, with an average concentration near 99 Bq/m³ — and judged northern residential radon "high," recommending testing and mitigation as a priority. It did not break out a standalone NWT figure, and there is no published Yellowknife-specific home-testing rate.
The two numbers (5.4% in 2012 vs a regional 20.5% in 2024) shouldn't be blended — they come from different studies, years, samples, and groupings, and the 2024 figure folds in Yukon. The defensible conclusion is not "NWT is low" or "NWT is high," but "NWT is under-tested, and the geology warrants caution" — see the next section. For how the territory compares with the provinces, see our radon levels by province breakdown.
What this means for you: with so little territorial data, a provincial-style average is not available to lean on — which removes any excuse not to test. A long-term test is the only way to know your own home's level.
Radon by region in the NWT
There is no public community-by-community radon breakdown for the Northwest Territories comparable to what exists for Yukon or the provinces — a gap we'd rather flag than paper over. Yellowknife, as the territory's largest community and the place with the most building activity, is the area most likely to generate testing data over time, but no Yellowknife-specific prevalence rate has been published. The 2024 national study treated the NWT only as part of a combined northern region.
What the geology suggests (below) is that the NWT is unlikely to be uniformly low, and that homes near uranium-bearing Shield bedrock — and homes affected by thawing permafrost — deserve particular attention. Until more community testing is done, the only reliable information about any specific home is a test of that home.
Why the NWT has radon: the geology
Radon levels track the amount of uranium and thorium in the ground beneath a home, and the Northwest Territories has two features that make its radon story distinctive.
Uranium-bearing bedrock and a mining history. Much of the NWT sits on the Canadian Shield, ancient igneous and metamorphic rock that is uranium-bearing in places. The region has a notable uranium and radium mining history — including the historic Port Radium mine on Great Bear Lake (operating from the 1930s) and the former Rayrock uranium mine northwest of Yellowknife — and former mine sites in the territory are documented sources of radon gas. Where homes sit on uranium-rich ground, elevated indoor radon is plausible.
Permafrost — a cap that is starting to lift. This is the feature that makes the North different from anywhere else in Canada. According to analyses summarized by the National Collaborating Centre for Environmental Health, permafrost can act as a "cap" that slows radon's escape from the ground — which may help keep some northern homes low today. But thawing permafrost is expected to release previously trapped radon, and modelling suggests homes built over thawing ground (especially with basements) could see indoor radon rise substantially and stay elevated for years. Homes built on piles or stilts — a common northern design — are less exposed to this pathway. Consistent with the warming trend, peer-reviewed monitoring near Yellowknife has measured a rising outdoor radon dose rate over the past two decades.
The science here is still developing, and these are projections, not measurements of your home. But the direction is clear enough to matter: the NWT's radon risk should be thought of as dynamic — potentially rising as the climate warms — rather than fixed at a single historic survey number. As always, the only way to know your home's level is to test it.
Is radon dangerous? The health risk in the NWT
Radon is classified by the International Agency for Research on Cancer as a Group 1 carcinogen — the highest category, the same as tobacco smoke and asbestos. Health Canada's current figures:
- Radon is the number one cause of lung cancer in non-smokers, and the second leading cause overall after smoking.
- About 16% of lung-cancer deaths in Canada are estimated to be radon-related — more than 3,000 deaths a year (Health Canada's fact sheet cites roughly 3,200).
- Health Canada estimates that a non-smoker exposed to high radon over a lifetime has roughly a 1 in 20 chance of developing lung cancer from it; for a smoker, the combined risk rises to about 1 in 3. Radon and tobacco smoke multiply each other's risk.
There is no NWT-specific lung-cancer-from-radon estimate. The national figures apply to NWT residents as they do to all Canadians.
Health Canada is careful to frame the risk proportionately, and so are we: there is no level of radon that is completely risk-free, the risk below the guideline is small, and it is ultimately each homeowner's choice what level of exposure they are willing to accept. Radon exposure is long-term, not acute — there are no immediate symptoms. The point isn't alarm; it's that radon is a measurable, fixable risk, and in an under-tested territory the measuring is the part that's missing.
The Health Canada guideline — and what your number means
Canada's guideline is 200 becquerels per cubic metre (Bq/m³), measured as an annual average in a normally occupied area of the home. It's a health-based guideline, not a hard legal limit for private homes. Health Canada's guidance:
- At or above 200 Bq/m³: take corrective action to reduce the level, within one year — and sooner the higher the result.
- Below 200 Bq/m³: no corrective action is recommended, though no level is risk-free; some households (especially where someone smokes) choose to act toward the WHO's more protective 100 Bq/m³ reference level. (See how the Health Canada, WHO, and US thresholds compare.)
Your result is a concentration, not a pass/fail — it exists on a spectrum. For a plain-language walkthrough of what different result ranges mean and what Health Canada recommends at each, see our guide on how to read your radon test results.
How to test for radon in the NWT
Testing is the only way to know your home's level, and it's straightforward:
- Use a long-term test of at least 91 days (three months). Health Canada recommends long-term testing because radon swings day to day and season to season; a 91+ day average is what reflects your real exposure. Short-term tests and digital "screeners" can flag a possible problem but are not suitable for deciding whether to act.
- The long northern heating season makes testing easy to time. A test that runs through the cold months, when homes are sealed up, gives a conservative reading — but you can start any time of year.
- Place the detector in the lowest lived-in level (often the basement if it's used; many northern homes sit on piles or slabs, in which case use the lowest occupied floor), in a room occupied more than four hours a day, about 30 cm off the floor and away from drafts, vents, and direct sun. Not the kitchen, bathroom, or laundry room.
- Use a C-NRPP-approved test. RadonTest.ca kits use an alpha-track detector analysed by a C-NRPP-certified laboratory. (For how long-term kits compare with continuous digital monitors, see our guide.)
Where to get your test: order a RadonTest.ca kit — the detector, analysis by a C-NRPP-certified laboratory (with an all-in-Canada analysis option), tracked shipping both ways, and your result delivered with clear Health Canada context are all included, and it ships to NWT addresses. One caution about cheaper retail kits: not every hardware-store kit is analysed by a C-NRPP-certified lab — see our comparison of hardware-store radon test kits.
When to retest. Health Canada recommends testing again after any renovation that affects your home's structure or ventilation, after energy retrofits (new windows, insulation, air sealing), or after excavation near the foundation. Given the permafrost-thaw concern, a home on ground that has noticeably settled or shifted is also worth retesting. If you install a mitigation system, retest every five years to confirm it's still working. There's no blanket "every five years" rule for an unmitigated home — the trigger is change.
For more, see when is radon testing season in Canada.
If your radon is high: mitigation in the NWT
A result above 200 Bq/m³ is a solvable problem (here's what to do if your radon is above 200 Bq/m³). Health Canada recommends hiring a C-NRPP-certified radon mitigation professional.
How it works. The standard, most effective method is active soil depressurization (ASD), also called sub-slab depressurization. A pipe is installed through the foundation slab and a continuously running fan draws radon from beneath the home and vents it safely outside. In most homes this reduces radon by more than 80%, and a system can usually be installed in less than a day. The fan must run continuously; the installer should check the system doesn't cause "back-drafting" of a furnace, water heater, or fireplace; and the work should be verified with a short-term test after activation and confirmed with a long-term test the following heating season — ideally not by the company that installed the system. (Homes built on piles or with crawl spaces may need a different approach, such as sub-membrane depressurization — a certified mitigator will assess this.)
What it costs. There is no published NWT-specific mitigation cost figure. Nationally, industry data compiled by Take Action on Radon puts the average at about $2,700, and Health Canada's own estimate for a typical sub-slab system is $2,000–$3,000. In the NWT — especially outside Yellowknife — costs can run higher because C-NRPP-certified mitigators are scarce in the North and may travel from southern provinces. Running the fan costs roughly $50–$75 a year in electricity, and the fan itself (about $200–$300) lasts 5–10+ years.
Find a certified professional. The Canadian National Radon Proficiency Program (C-NRPP) — run by the Canadian Association of Radon Scientists and Technologists with Health Canada oversight — certifies radon measurement professionals, mitigation professionals, and labs. Health Canada recommends using a C-NRPP-certified contractor. Search the directory at c-nrpp.ca/find-a-professional; in the North you may need to contact a professional who serves the NWT from elsewhere. RadonTest.ca does not perform mitigation or recommend specific companies.
See also: radon mitigation cost across Canada and how to choose a licensed radon mitigator.
The NWT's radon rules and protections
The Northwest Territories has the thinnest radon-specific framework of any jurisdiction in this series — a fact the territory's own legislators have flagged.
New-home warranty
The NWT has no mandatory new-home warranty program, and nothing covers radon. Unlike Ontario, where the Tarion warranty covers radon mitigation up to $50,000, an NWT buyer of a new home has no equivalent statutory backstop for radon.
The building code (new construction)
The Northwest Territories follows the National Building Code of Canada, which includes radon-control rough-in provisions for new homes. In practice, building-code enforcement is strongest where there is permit-and-inspection capacity — principally Yellowknife — and is more limited in smaller and unincorporated communities. The building code governs new construction only and does not require anything of existing homes. More detail: Canadian building codes and radon.
Programs and awareness
There is no territorial radon grant, kit program, or dedicated awareness campaign. The NWT Legislative Assembly's 2026 jurisdictional review of radon supports across Canada stated plainly that the territory has "no territorial programs that explicitly support radon mitigation or testing," and Take Action on Radon notes it has no partner groups working on radon awareness in the NWT. That the territory commissioned this review is itself a sign the gap is now on the legislative radar.
Selling or buying a home: disclosure in the NWT
Radon disclosure is not mandatory in the NWT. There is no territorial property-disclosure statement with a radon line (only Nova Scotia, New Brunswick, Quebec, and British Columbia have one), and transactions are generally governed by "buyer beware" (caveat emptor). However, a known elevated radon level is the kind of hidden ("latent") defect a seller who is aware of it should disclose. If you've tested and know your level is high, that knowledge should be disclosed; if you're buying, make radon part of your due diligence. See radon when buying or selling a home in Canada. Renting, or renting out a property? See our guides for landlords and renters.
Radon in NWT workplaces
No NWT-specific binding radon exposure limit was identified in the territory's occupational-health regulations (administered through the Workers' Safety and Compensation Commission); general health-and-safety duties apply. Separately, federally regulated workplaces in the NWT (banks, telecom, interprovincial and air transport, federal operations) fall under a new federal rule, SOR/2026-10, which sets a binding workplace limit of 200 Bq/m³ (replacing the old 800 Bq/m³ standard) and comes into force around early 2027.
Financial help in the NWT
- There is no NWT provincial/territorial radon grant or tax credit. This is confirmed by the NWT Legislative Assembly's own 2026 review.
- Lungs Matter (Canadian Lung Association) offers up to $1,500 toward home radon mitigation, prioritizing people diagnosed with lung cancer and lower-income households. The program is described as national; because there is no NWT lung association, confirm territorial eligibility with the Canadian Lung Association.
- There is currently no open federal radon-mitigation grant for the general public.
If the cost of mitigation is a barrier, it's worth checking whether any general territorial home-repair or housing-assistance program (for example, through the NWT Housing Corporation) can be applied — confirm directly with the program, as radon is rarely named explicitly.
Frequently asked questions
Is radon a problem in the Northwest Territories? It may be, but the territory is under-tested. Health Canada's older survey found 5.4% of NWT homes above the guideline (small sample), while a 2024 study placed the combined NWT-and-Yukon north at about 1 in 5. The geology — uranium-bearing bedrock plus thawing permafrost — is reason enough to test your own home.
What is a risk-free radon level in the NWT? There is no completely risk-free level — Health Canada's guideline is 200 Bq/m³, the level above which it recommends taking action within a year. The risk below the guideline is small but not zero, and the WHO references a more protective 100 Bq/m³.
Does thawing permafrost affect radon? Researchers expect it can. Permafrost can trap radon underground; as it thaws, previously trapped radon may be released, and modelling suggests some homes could see indoor levels rise. This is emerging science and a reason to treat northern radon risk as something that can change over time — test, and retest if your ground shifts.
Does any warranty or grant cover radon in the NWT? No. There is no NWT new-home warranty covering radon and no territorial radon grant. The national Lungs Matter program may help — confirm territorial eligibility with the Canadian Lung Association.
How much does radon mitigation cost in the NWT? There's no NWT-specific figure; nationally the average is about $2,700 and Health Canada estimates $2,000–$3,000 for a typical system. In the NWT it can cost more because certified mitigators are scarce in the North.
How long does a radon test take? At least 91 days (three months) for a valid long-term result. Short-term "screeners" can flag a possible problem but aren't suitable for deciding whether to act.
Test your NWT home
Radon is invisible, and in an under-tested territory the only information you can trust about your home is your home's own result. A long-term test is the way to get it.
Order your RadonTest.ca kit → — lab analysis by a C-NRPP-certified laboratory (with an all-in-Canada analysis option), tracked shipping both ways, and your result delivered with clear Health Canada context.
Sources
- Health Canada — Radon guideline (corrective action within 1 year), modified 2025-09-24. https://radontest.ca/links/hc-guideline
- Health Canada — Radon: What you need to know ("1 in 5 homes," 16% of lung cancers, ~3,200 deaths), 2025 edition. https://radontest.ca/links/hc-what-you-need-to-know
- Health Canada — Cross-Canada Survey of Radon Concentrations in Homes, Final Report (NWT 5.4%, n=185), 2012. https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/radiation/cross-canada-survey-radon-concentrations-homes-final-report-health-canada-2012.html
- Evict Radon National Study / University of Calgary — 2024 Cross-Canada Survey of Radon (combined Northern region NWT+YT ~20.5%). https://crosscanadaradon.ca/survey/
- NWT Legislative Assembly — Jurisdictional Scan of Public Radon Testing and Mitigation Supports in Canada (Tabled Document 443-20(1); "no territorial programs that explicitly support radon mitigation or testing"), tabled 2026. https://www.ntlegislativeassembly.ca/sites/default/files/tabled-documents/2026-02/TD%20443-20(1)%20Radon.pdf
- National Collaborating Centre for Environmental Health — Climate change, the Arctic, and radon gas: a rising threat from the ground (permafrost cap; thaw-driven radon release), 2022. https://ncceh.ca/resources/blog/climate-change-arctic-and-radon-gas-rising-threat-ground
- Health Canada — Reducing radon levels in your home (>80% reduction; C-NRPP), modified 2025-10-09. https://radontest.ca/links/hc-mitigation-guide
- Health Canada — Guide for radon measurements in homes (91-day test; retest triggers; 5-year retest for mitigated homes), modified 2025-12-22. https://radontest.ca/links/hc-measurements-guide
- Health Canada — Radon Reduction Guide for Canadians (ASD mechanism; back-draft; operating cost), modified 2025-09-24. https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/radiation/radon-reduction-guide-canadians-health-canada.html
- Take Action on Radon — Reducing radon (cost data; ASD explainer); Northwest Territories program page (no NWT awareness groups). https://takeactiononradon.ca/protect/reducing-radon/ and https://takeactiononradon.ca/provinces/northwest-territories/
- Canada Gazette Part II — SOR/2026-10 (federal workplace 200 Bq/m³, in force ~early 2027), 2026-02-11. https://gazette.gc.ca/rp-pr/p2/2026/2026-02-11/html/sor-dors10-eng.html
Lab analysis is performed independently by a C-NRPP-certified laboratory. Results are reported against the Health Canada guideline of 200 Bq/m³. RadonTest.ca coordinates kit logistics and sample submission only — it does not interpret or modify lab results and does not provide medical, legal, or warranty advice. Information attributed to Health Canada, the Government of the Northwest Territories, and others is summarized from the public sources listed above; confirm time-sensitive details (building-code requirements, program availability, workplace rules) with the responsible body.