A note before you read. This is general consumer information for Newfoundland and Labrador homeowners, buyers, sellers, landlords, and renters, drawn from publicly available Health Canada, the City of St. John's, Take Action on Radon, Evict Radon, and other 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 Newfoundland & Labrador at a glance
- Newfoundland and Labrador is a moderate-radon province with real local hotspots. Health Canada's 2012 survey found about 5% of NL homes above the 200 Bq/m³ guideline (up to 10% in some regions). Recent community testing has found higher local rates — about 10–11% of tested St. John's homes, and 29% in Conception Bay South.
- Radon is the number one cause of lung cancer in non-smokers — about 16% of lung-cancer deaths in Canada, more than 3,000 a year.
- The Health Canada guideline is 200 Bq/m³ (annual average). Above it, Health Canada recommends acting within one year — sooner the higher the level.
- St. John's runs a free radon test-kit program each fall (and several other NL towns now do too) — popular and limited, so a year-round kit is the dependable option.
- Building-code radon protection is up to each municipality in NL — it's not a uniform province-wide rule, so a new NL home may or may not have a radon rough-in.
- A valid test takes at least 91 days (about three months). Fixing a home usually costs in the low thousands and installs in about a day.
How much radon is in Newfoundland & Labrador homes?
Radon is a naturally occurring radioactive gas — colourless, odourless, tasteless — produced as uranium in soil and rock breaks down, then seeping indoors.
- Health Canada's Cross-Canada Survey (2012) found about 5% of NL homes above the 200 Bq/m³ guideline, with up to 10% in some regions.
- The 2024 Cross-Canada Radon Survey reports the Atlantic region as a whole at roughly 1 in 3 homes above the guideline, but it does not publish a standalone NL figure, so that regional number shouldn't be read as NL's rate.
- Recent local testing is the most useful NL-specific data. The City of St. John's free-kit program (winter 2024–25, ~280 homes) found about 10–11% of tested homes above the guideline — and a Take Action on Radon project in Conception Bay South found 29% of tested homes above it, marking CBS as a clear local hotspot.
These community numbers come from self-selected testing, not random samples, so treat them as indicative rather than precise prevalence. The throughline: NL is moderate overall, but specific communities — and specific homes anywhere — can be high. Health Canada uses "1 in 5" as its national headline. (For the national picture, see radon levels by province.)
What this means for you: a provincial or even a city average can't tell you about your house. Two homes on the same street can read very differently. A long-term test is the only way to know your own number.
Find your city: see our local guide for St. John's.
Why Newfoundland & Labrador has radon: the geology
Radon levels track the amount of uranium in the ground beneath a home. Newfoundland's eastern Avalon region — including the St. John's area — sits on older volcanic and sedimentary rock, and the province's elevated readings are consistent with the uranium-bearing granitic and shale bedrock found across parts of the island (shale itself is a radon-relevant, uranium-bearing rock type). Health Canada's general principle applies: radon is "usually higher in areas where there is a higher amount of uranium in underlying rock and soil." The local geology helps explain why communities like Conception Bay South run higher — but, as everywhere, the picture varies house by house, which is why testing matters more than any map.
Is radon dangerous? The health risk
Radon is classified by the International Agency for Research on Cancer as a Group 1 carcinogen — the highest category, alongside 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 a year.
- Health Canada estimates 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.
Health Canada frames the risk proportionately, and so do 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 acts over the long term, with no immediate symptoms. The point isn't alarm — radon is measurable and fixable, and testing is inexpensive. (To separate fact from fiction, see our top radon misconceptions.)
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.
Your result is a concentration, not a pass/fail — it sits on a spectrum. For what each range means, see how to read your radon test results and our comparison of the Health Canada, WHO, and US thresholds.
How to test for radon in NL
Testing is the only way to know your home's level — especially in a province with local hotspots:
- Use a long-term test of at least 91 days (about three months). Radon swings day to day and season to season; a 91+ day average reflects your real exposure. Short-term tests are only for checking a mitigation system, never for deciding whether to act.
- The heating season (roughly October–April) is ideal, because Health Canada recommends that at least 91 days of the test fall within it; a test that runs largely outside the heating season can underestimate your annual average.
- Place the detector in the lowest lived-in level (often the basement if it's used), 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. (St. John's and several other NL towns run free seasonal kit programs each fall, but they're limited and registration closes quickly — a kit you order is available year-round.) 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, or after excavation near the foundation; and every five years if you have a mitigation system, to confirm it's still working. (See when is radon testing season in Canada.)
If your radon is high: mitigation in NL
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 through the foundation slab and a continuously running fan draw radon from beneath the home and vent it outside before it can enter your living space. In most homes this reduces radon by more than 80%, and a system often installs in about a day. A good contractor will run the fan continuously (never off), check that the system doesn't cause "back-drafting" of a furnace or water heater, and verify the work with a follow-up long-term test the next heating season.
What it costs. Health Canada estimates $2,000–$3,000 for a typical sub-slab system, and national data from Take Action on Radon averages about $2,700 (complex buildings cost more). Running the fan adds roughly $50–$75 a year in electricity. (See radon mitigation cost in Canada.)
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. Search the directory at c-nrpp.ca/find-a-professional. RadonTest.ca does not perform mitigation or recommend specific companies. (See also how to choose a licensed radon mitigator.)
Newfoundland & Labrador's radon rules and protections
NL's distinctive features are its free city test-kit programs and a municipally-driven building-code approach.
Free city test-kit programs
The City of St. John's runs a free radon test-kit program each fall (around Radon Action Month), distributing long-term kits to residents — about 345 kits in 2024 and roughly 250 (50 per ward) in 2025. It's popular and oversubscribed, with registration closing quickly. Several other NL communities — including Conception Bay South, Mount Pearl, Paradise, and Torbay — now run their own programs, often through Take Action on Radon's "100 Radon Test Kit Challenge." These are great when you can get one; outside the program window, a kit you order is the dependable route.
Building Code: radon protection is up to each municipality
This is an important NL-specific nuance. Unlike provinces that require a radon rough-in province-wide, Newfoundland and Labrador leaves it to each municipality to decide whether to adopt radon-control building measures. For example, Mount Pearl has made a "radon stub pipe" (a rough-in) mandatory in new houses, while other municipalities may not require one. So whether a new NL home has a radon rough-in depends on where it was built — another reason not to assume a newer home is protected, and to test. (For background, see Canadian building codes and radon.)
Selling a home: disclosure
NL follows "buyer beware" (caveat emptor) for visible defects, but sellers have a duty to disclose known material latent (hidden) defects — and a known, unmitigated high radon result would fall into that category. The provincial REALTORS' property condition disclosure statement is voluntary, and NL is not among the provinces Health Canada lists as having a dedicated radon line in their disclosure statement. Practical takeaway: if you've tested and know your level is high, disclose it; if you're buying, ask. (See radon when buying or selling a home in Canada.)
New-home warranty and workplaces
A new-home warranty is voluntary in NL (through the Atlantic Home Warranty Program) and does not explicitly cover radon — unlike Ontario's Tarion warranty (which covers radon mitigation up to $50,000). NL's workplace safety rules don't set a specific radon limit; separately, federally regulated workplaces in NL fall under the new federal rule SOR/2026-10, which sets a binding limit of 200 Bq/m³ (replacing the old 800 Bq/m³), coming into force around February 2027. (For warranty details across Canada, see does your new home warranty cover radon?; for rentals, see landlords and renters.)
Financial help in Newfoundland & Labrador
- Free seasonal test kits from the City of St. John's and other NL town programs (when registration is open).
- No dedicated NL provincial radon grant exists (a provincial radon plan has been publicly called for but not established); a former $800 grant toward C-NRPP mitigator training closed in 2022.
- Lungs Matter (Canadian Lung Association) — a national grant of up to $1,500 toward mitigation, prioritizing people diagnosed with lung cancer and lower-income households (a long-term C-NRPP test result at or above 200 Bq/m³ is required).
- There is currently no open federal radon-mitigation grant for the general public.
Frequently asked questions
What is a risk-free radon level in NL? No level is completely risk-free. Health Canada's guideline is 200 Bq/m³, the level above which it recommends acting within a year. The risk below the guideline is small but not zero, and the WHO references a more protective 100 Bq/m³.
How common is high radon in Newfoundland & Labrador? Moderate overall — about 5% of NL homes above the guideline in Health Canada's 2012 survey — but higher in places: recent testing found about 10–11% of St. John's homes and 29% in Conception Bay South.
Where can I get a free radon test in NL? The City of St. John's (and towns like Conception Bay South, Mount Pearl, Paradise, and Torbay) run free kit programs each fall. They're limited and close quickly, so if you miss the window, a kit can be ordered year-round.
Do new NL homes have radon protection built in? It depends on the municipality — NL leaves radon-control building measures to each town. Some (like Mount Pearl) require a radon rough-in; others may not. Don't assume a new home is protected; test it.
Does NL's new-home warranty cover radon? No. NL's new-home warranty is voluntary and does not cover radon — unlike Ontario's Tarion warranty.
How long does a radon test take? At least 91 days (about three months) for a valid long-term result. Short-term tests aren't suitable for deciding whether to act.
Test your Newfoundland & Labrador home
NL is moderate overall but has real local hotspots like Conception Bay South — and the only way to know your home's level is a long-term test.
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: What you need to know ("1 in 5 homes," 16% of lung cancers, >3,000 deaths, >80% reduction), 2025. https://radontest.ca/links/hc-what-you-need-to-know
- Health Canada — About radon / Radon guideline (200 Bq/m³; corrective action within 1 year), modified 2025-09-24. https://www.canada.ca/en/health-canada/services/health-risks-safety/radiation/radon/about.html
- Health Canada — Reduction Guide for Canadians ($2,000–$3,000; fan operating cost; 1-in-20 / 1-in-3 risk; mechanism), 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
- Health Canada — Guide for radon measurements in homes (91-day test, season guidance, retest triggers), modified 2025-12-22. https://radontest.ca/links/hc-measurements-guide
- City of St. John's — Radon testing (free kit program; ~10% of tested homes above guideline, 2024–25). https://www.stjohns.ca/en/living-in-st-johns/radon-testing.aspx
- Take Action on Radon — Conception Bay South Community Report (29% above guideline), Oct 2025. https://takeactiononradon.ca/wp-content/uploads/2025/10/Conception-Bay-South-Community-Report-October-2025.pdf
- Take Action on Radon — Atlantic (HC 2012 NL 5%/up to 10%; NL community programs; building-code note). https://takeactiononradon.ca/provinces/atlantic/
- 2024 Cross-Canada Radon Survey (Evict Radon / University of Calgary) — Atlantic region figure (not NL-specific). https://crosscanadaradon.ca/survey/
- Canada Gazette Part II — SOR/2026-10 (federal workplaces: 200 Bq/m³, in force ~Feb 2027). https://gazette.gc.ca/rp-pr/p2/2026/2026-02-11/html/sor-dors10-eng.html
- Canadian Lung Association — Lungs Matter radon mitigation grant (up to $1,500). https://www.lung.ca/air-quality/radon/lungs-matter-radon-mitigation-support
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 City of St. John's, and others is summarized from the public sources listed above; confirm time-sensitive details (free-kit availability, municipal building-code requirements, disclosure obligations, program availability) with the responsible body.