Radon in St. John's (2026): What the Data Shows, the Free City Test Kit Program, and What St. John's Homeowners Should Do

Flat-vector map of Canada with a coral red pin marking St. John's, Newfoundland and Labrador, alongside a circular badge showing 10% — share of St. John's homes above the Health Canada radon guideline per a 2024-25 local study

A note before you read. This article is general health and home-testing information for St. John's homeowners, drawn from Health Canada, the City of St. John's, Newfoundland and Labrador Health and Community Services, and the Canadian Cancer Society. It is not medical advice. See full disclaimers at the bottom.

If you live in St. John's and you've been wondering whether radon is a real concern in Newfoundland and Labrador, the data answers clearly. The City of St. John's ran its own dedicated radon testing program in winter 2024–2025, distributing 345 test kits and analyzing 278 completed 91-day alpha-track tests. The result: about 10% of tested St. John's homes had radon levels above the Health Canada 200 Bq/m³ guideline — meaningfully higher than the NL provincial average of about 5%, and in line with what would be expected from St. John's bedrock geology on the Avalon Peninsula.

What's distinctive about St. John's is the free radon testing program the City actively runs for residents — one of the more comprehensive municipal radon awareness initiatives in Atlantic Canada. The 2025 program returned with free test kits available, distributed 50 per ward across the City. Combined with notable provincial hotspots — Conception Bay South has tested with as high as 30% of homes above the Health Canada guideline — the case for testing in the St. John's / Avalon region is meaningful.

This guide walks through the St. John's and NL data, explains why parts of Newfoundland have notable radon, lays out the practical step-by-step from "I want to know" to "result in hand," and details the City's free testing program along with other local resources.

TL;DR for St. John's homeowners

  • About 10% of tested St. John's homes had radon levels above the Health Canada 200 Bq/m³ guideline in the City's 2024–2025 program (278 long-term tests analyzed).
  • NL provincial average: about 5% of homes above the guideline (2012 Cross-Canada Survey); some NL regions reach up to 10% by current testing.
  • Conception Bay South has documented as high as 30% of tested homes above the Health Canada guideline — a notable Avalon-region hotspot.
  • The City of St. John's offers free radon test kits to City residents through an ongoing program (50 kits per ward in the 2025 cycle).
  • The only way to know your home's level is to test it. Long-term test, 91+ days, ideally during the heating season. Order a $89 long-term radon test kit → (or check current availability of the City's free kit program).

Table of contents

  1. What the published St. John's and NL radon data shows
  2. The City of St. John's free radon test kit program
  3. Why St. John's radon is elevated — geology, climate, and construction
  4. What to do as a St. John's homeowner
  5. Local St. John's and NL resources
  6. FAQ — St. John's-specific questions
  7. Disclaimers
  8. Sources

What the published St. John's and NL radon data shows

St. John's has surprisingly detailed local radon data thanks to the City's dedicated testing program. The most recent published results:

  • City of St. John's 2024–2025 testing program: 345 test kits distributed; 278 homes participated using 91-day alpha track tests; about 10% of tested homes had radon levels above the Health Canada guideline of 200 Bq/m³. This represented about 1% of the City's residential dwellings tested.
  • NL provincial average (2012 Cross-Canada Survey): about 5% of homes above the 200 Bq/m³ guideline; some NL regions reach up to 10%.
  • Conception Bay South: documented as high as 30% of tested homes above the Health Canada guideline — a notable Avalon-region hotspot.
  • City of St. John's continues the free radon test kit program in 2025, with 50 kits distributed per ward.

Sources: City of St. John's — Radon Testing; City of St. John's — Free Radon Test Kits Return for 2025; Take Action on Radon — Atlantic provinces; Government of NL — Air Quality

The takeaway: while NL's provincial-average rate is lower than Manitoba, Saskatchewan, or New Brunswick, St. John's specifically and the Avalon Peninsula in particular have meaningful radon concerns — about 1 in 10 St. John's homes tested above the Health Canada guideline, and Conception Bay South has documented dramatically higher rates. The only way to know your specific home's level is a long-term radon test.

Order a $89 long-term radon test kit →

The City of St. John's free radon test kit program

The City of St. John's operates one of the more proactive municipal radon awareness programs in Atlantic Canada. Key features:

  • Free test kits for City residents — distributed seasonally (typically fall, ahead of the winter testing window).
  • 2025 program: 50 test kits distributed per City ward, with alpha track long-term tests designed for the standard 91-day winter testing protocol.
  • Results returned to the City support ongoing community-level data on St. John's radon profile.

Verify current availability and eligibility directly at stjohns.ca before relying on the program. Distribution quantities, eligibility criteria, and program timing are subject to change with City Council decisions and budget cycles.

For St. John's homeowners deciding between testing options:

  • City of St. John's free kit: best option if you qualify and program kits are currently available, with the trade-off of distribution timing windows and limited quantities (50 per ward).
  • RadonTest.ca $89 all-in kit: available online year-round, delivered to your door anywhere in Canada, prepaid tracked Canada Post return label, analysis at C-NRPP-listed Lex Scientific in Guelph, lab report PDF delivered to your inbox.

Both pathways use the same Health Canada–recommended long-term test type (91+ days, alpha track, lab-analyzed). Choose based on whether free kits are currently available in your ward.

Why St. John's radon is elevated — geology, climate, and construction

Three factors influence St. John's residential radon profile:

1. Geology. St. John's and the Avalon Peninsula sit on a varied geological setting — including granite and other igneous and metamorphic rocks containing variable but often elevated uranium content. Newfoundland's bedrock varies substantially across the island, and the Avalon Peninsula (where St. John's, Conception Bay South, and much of NL's population are located) tends to have higher background radon than some other parts of the province. Conception Bay South's notably elevated rate (up to 30%) reflects local geology in that specific Avalon community.

2. Climate. St. John's has a long heating season — typically October through May — with cold, wet Atlantic winters that lead to homes being sealed against the weather. Furnaces and HVAC systems run regularly, and the natural "stack effect" actively pulls soil gas into basements during the heating season.

3. Building construction. St. John's housing stock includes older heritage homes (especially in downtown and the older central neighbourhoods like Georgestown, Rabbittown, and the area near Memorial University), suburban single-family construction (Mount Pearl, Paradise, and outer St. John's), and rural housing in surrounding Avalon communities. Older homes typically lack any radon construction features; newer construction has been subject to NL's adoption of NBC radon provisions.

The combination — varied Avalon bedrock geology + long Atlantic heating season + mixed-era housing stock — is why some St. John's homes show meaningful radon and why the City has invested in a dedicated testing awareness program.

What to do as a St. John's homeowner

Step-by-step:

Step 1: Test (long-term, 91+ days). Health Canada's recommended test for a homeowner mitigation decision is a long-term alpha-track lab test, deployed for at least 91 days during the heating season (October–May in St. John's), in the lowest lived-in level of your home. Two pathways:

  • City of St. John's free program (stjohns.ca): if you're a City resident and kits are currently available in your ward.
  • Online order: RadonTest.ca $89 all-in kit — kit + tracked outbound + prepaid tracked Canada Post return label + analysis at Lex Scientific in Guelph (a C-NRPP-listed Canadian lab). Available year-round and to all of NL including communities outside the City of St. John's.

Step 2: Read your result. Below 200 Bq/m³, no mitigation is required (Health Canada recommends retesting every 5 years). Above 200 Bq/m³, mitigation is recommended. See our How to Read Your Radon Test Results and What to Do If Your Radon Level Is Above 200 Bq/m³ guides.

Step 3: Mitigate, if needed. A C-NRPP-certified mitigation contractor installs a sub-slab depressurization system at a typical Atlantic Canada cost of $2,500–$4,500. These systems typically reduce radon by up to 95% (Health Canada cites reductions of more than 80%; CARST cites up to 95%). Find a St. John's–area C-NRPP-certified mitigator via the C-NRPP Find a Professional tool.

Step 4: Apply for the Lungs Matter grant. The Canadian Lung Association's Lungs Matter program offers up to $1,500 toward radon mitigation for eligible Canadian homeowners.

Step 5: Verify. Once mitigation is complete, run an independent post-mitigation test to confirm levels are below 200 Bq/m³ and stay that way.

Order your St. John's kit — $89 →

Local St. John's and NL resources

Note on NL building code. Newfoundland and Labrador adopts the National Building Code (currently NBC-based), which requires a Level 1 radon "rough-in" (capped vent pipe through the slab + soil gas barrier + sealed perimeter) in new construction. See our Canadian Building Codes and Radon guide.

Note on NL real estate disclosure. NL uses standard provincial property disclosure principles, and the common-law latent-defect doctrine applies. A known elevated radon reading is generally treated as a material defect requiring disclosure. See our Real Estate Radon Guide for the cross-Canadian framework.

FAQ — St. John's-specific questions

How common is high radon in St. John's? Per the City of St. John's 2024–2025 radon testing program (278 long-term tests analyzed), about 10% of tested St. John's homes had radon levels above the Health Canada 200 Bq/m³ guideline. The NL provincial average is about 5% above guideline; some NL regions reach up to 10%. Conception Bay South has documented dramatically higher rates — up to 30% above guideline. The only way to know your home's specific level is to test it.

Where can I get a free radon test kit in St. John's? The City of St. John's distributes free radon test kits to City residents (typically 50 kits per ward, with seasonal distribution windows). Verify current availability and eligibility directly at the City's radon testing page before counting on a free kit. If the program is between distribution cycles or you're outside the City of St. John's, you can order a RadonTest.ca $89 all-in kit online.

Why is St. John's radon higher than the rest of NL? The Avalon Peninsula (where St. John's, Conception Bay South, and much of NL's population are located) sits on geology containing variable but often elevated uranium content — including granite and other igneous/metamorphic rocks. Some Avalon areas, notably Conception Bay South, have documented dramatically higher rates.

Why are Conception Bay South radon levels so much higher? Conception Bay South's bedrock geology contains higher uranium concentrations than many other Avalon-area locations. Local public health and the Government of NL have flagged Conception Bay South as a documented elevated-radon area within the broader Avalon region.

Are some St. John's neighbourhoods worse than others? Yes, in broad terms — St. John's geology varies across the City, and the City's 2024–2025 testing program data has informed local awareness of variation. Individual home levels vary substantially even within neighbourhoods, and the only way to know your specific home's level is to test it.

Does my newer St. John's home have a radon rough-in? If your home was built under NL's adoption of NBC radon provisions, it should have a capped vent pipe stub through the basement slab. The rough-in is infrastructure for future mitigation, not active reduction.

How much does radon mitigation cost in St. John's? Typical Atlantic Canada residential mitigation costs are $2,500–$4,500 for a sub-slab depressurization system installed by a C-NRPP-certified contractor. The Canadian Lung Association's Lungs Matter program may offset up to $1,500.

Where can I buy a long-term radon test kit in St. John's? Two options: (1) the City of St. John's free program if eligible and currently available; (2) a RadonTest.ca $89 all-in long-term kit ordered online and delivered to anywhere in NL — kit + tracked outbound + prepaid tracked Canada Post return label + analysis at a C-NRPP-listed Canadian lab.

Do I have to disclose elevated radon when I sell my St. John's home? NL uses standard provincial property disclosure principles, and the common-law latent-defect doctrine applies. A known elevated radon reading is generally treated as a material defect requiring disclosure. See our full Real Estate Radon Guide, and consult a NL real estate lawyer for any specific transaction.

When is the best time of year to test in St. John's? The heating season — October through May in St. John's (longer than most Canadian cities due to the Atlantic climate) — produces the highest indoor radon levels and is the recommended testing window per Health Canada.

Where can I find a C-NRPP-certified radon mitigator in St. John's? The C-NRPP Find a Certified Professional directory lists certified measurement and mitigation professionals by area.

Test your St. John's home — $89, all in (or free via the City)

About 10% of tested St. John's homes — 1 in 10 — have radon above the Health Canada guideline per the City's 2024–2025 dedicated program. The City offers free test kits to residents when available, and online options like the RadonTest.ca $89 all-in kit are available year-round. Either way, the action is the same: a long-term radon test that produces a real lab result.

RadonTest.ca — $89 all-in (plus applicable tax). Long-term 91-day alpha-track test kit. C-NRPP-listed device. Analysed at Lex Scientific in Guelph, Ontario — Canadian lab, C-NRPP listed, ISO/IEC 17025 accredited by CALA. Tracked Canadian shipping both ways. Written lab report PDF delivered to your inbox.

Order — $89 →

Important disclaimers

Not medical, legal, or warranty advice. This article provides general health and home-testing information for St. John's homeowners drawn from publicly available City of St. John's, Government of Newfoundland and Labrador, Health Canada, and Canadian Cancer Society materials. It is not medical advice, legal advice, or warranty advice. Consult a qualified professional for specific decisions.

Statistics and citations. The "about 10% of tested St. John's homes" figure and the 278/345 test counts are from the City of St. John's Radon Testing program 2024–2025 reporting. NL provincial figures are from Health Canada's 2012 Cross-Canada Survey of Radon Concentrations in Homes with subsequent provincial data. The Conception Bay South 30% figure reflects publicly available regional testing reports. National figures are from Health Canada's Radon: What You Need to Know fact sheet (2025). Sources update published figures periodically; figures cited reflect the sources as of May 2026.

City of St. John's free testing program. Specific terms (eligibility, kit availability, distribution timing, ward allocation) of the City's free radon testing program are subject to change with City Council decisions and budget cycles. Verify current availability directly at stjohns.ca before counting on a free kit. RadonTest.ca is independent from the City of St. John's and does not administer the City's program.

Local St. John's / NL data. Statements about St. John's radon levels reflect published City and provincial materials. Radon levels vary substantially even between adjacent homes; community-level statistics do not substitute for a home-specific long-term test.

Mitigation cost. The $2,500–$4,500 mitigation cost range is a typical Atlantic Canada residential figure. Actual costs vary by home, foundation, complexity, and contractor.

Lungs Matter grant. Eligibility, grant amounts, and program availability for the Canadian Lung Association's Lungs Matter program may change. Verify directly at lung.ca before relying on the program.

Real estate disclosure. Statements about NL real estate disclosure reflect the general common-law latent-defect framework. Specific obligations for any individual transaction depend on the facts; consult a NL real estate lawyer.

No diagnosis or treatment claims. RadonTest.ca sells radon test kits. We do not diagnose, treat, or prevent disease.

No warranty as to completeness. RadonTest.ca makes no warranty as to the completeness or accuracy of the information herein and accepts no liability for decisions made in reliance on this article.

Sources & further reading

St. John's- and NL-specific

Health Canada / national

National associations and grants

Related RadonTest.ca articles