A note before you read. This article is general health and home-testing information for St. Catharines-area and Niagara Region homeowners and renters, drawn from publicly available Health Canada, CARST, Niagara Region Public Health, Tarion, and Canadian Cancer Society materials. It is not medical advice and is not legal advice. See full disclaimers at the bottom.
St. Catharines, the largest city in Niagara Region, sits on glacial deposits over sedimentary bedrock just below the Niagara Escarpment. The escarpment is a major geological feature that runs through Niagara Region, and its sedimentary bedrock includes uranium-bearing parent material in localized sub-areas. Health Canada's 2012 Cross-Canada Radon Survey places Ontario at roughly the Canadian national average — about 7% of homes at or above the 200 Bq/m³ Health Canada residential guideline — with substantial regional variation. Niagara Region warrants routine residential radon testing, particularly in escarpment-adjacent neighbourhoods.
Whether you live in St. Catharines, Niagara Falls, Welland, Thorold, Niagara-on-the-Lake, Pelham, Lincoln, or Grimsby, radon testing is the basic indoor-air-quality due-diligence check.
TL;DR for St. Catharines and Niagara homeowners and renters
- Health Canada residential guideline: 200 Bq/m³ (Health Canada — Radon: About).
- Test your Niagara-area home with a 91-day long-term alpha-track test in the lowest lived-in level during the heating season (October–April).
- Order a $89 long-term radon test kit →
- Ontario new builds with APS signed on or after February 1, 2021 may qualify for up to $50,000 of Tarion radon mitigation coverage within a 7-year window. Meeting qualification criteria does not guarantee a claim will be approved.
Table of contents
- Why Niagara Region homes need testing
- What Ontario data show
- How to test your Niagara home
- Mitigation in Niagara
- Ontario new-home buyers: Tarion coverage
- Real estate & disclosure in Ontario
- Renters in Niagara
- FAQ — Niagara-specific questions
- Order your test kit
- Important disclaimers
- Sources & further reading
Why Niagara Region homes need testing
The Niagara Region sits on glacial deposits over sedimentary bedrock, with the Niagara Escarpment as a defining geological feature. The escarpment includes localized uranium-bearing parent material that can produce indoor radon. Combined with the region's housing stock (heritage homes in St. Catharines and Niagara-on-the-Lake, plus newer subdivisions in Welland, Pelham, and Grimsby), routine residential testing is warranted.
Three factors:
- Geology. Glacial deposits over sedimentary bedrock, with the Niagara Escarpment introducing localized geological variation.
- Long heating season. Southern Ontario winters drive months of furnace operation, producing stack-effect pressure differentials.
- Building stock. Niagara Region has heritage construction plus extensive newer-subdivision development with finished basements used as living space.
Niagara Region Public Health has historically supported radon awareness programming.
What Ontario data show
Health Canada's 2012 Cross-Canada Radon Survey reports Ontario at roughly the Canadian average overall (~7% of homes ≥ 200 Bq/m³), with substantial regional variation. The Niagara Region's escarpment geology adds localized variation; specific Niagara homes — particularly those in escarpment-adjacent neighbourhoods — can show elevated readings. Test your specific home.
How to test your Niagara home
Per Health Canada's published guidance (Guide for Radon Measurements in Residential Dwellings), the Canadian residential standard is a long-term test of at least 91 days using an alpha-track or electret detector, deployed in the lowest lived-in level during the heating season (October–April).
For most Niagara-area homes:
- Finished basement if used as a bedroom, home office, gym, rec room, or rental suite — that's where to test.
- Lowest sleeping level if the basement is unfinished.
- Main floor only if the home has no basement.
Place the kit at breathing height (1–2 metres), away from drafts, exterior walls, windows, and HVAC supply registers. Keep it in place for at least 91 days, then return to the lab.
Order your $89 long-term radon test kit →
Mitigation in Niagara
If your test exceeds 200 Bq/m³, the standard Canadian fix is active sub-slab depressurization (SSD). Typical Niagara-area cost: $2,500–$4,500 for a standard SSD installation.
Always use a C-NRPP-certified Mitigation Professional. Verify on the C-NRPP Find a Professional directory, filter by Ontario. Niagara Region is served by Hamilton-area and southwestern Ontario C-NRPP-certified contractors.
For the full mitigator-selection playbook, see our How to Choose a Licensed Radon Mitigator in Canada guide. After mitigation, run an independent post-mitigation test.
Ontario new-home buyers: Tarion coverage
Niagara Region has had significant new-build subdivision growth, particularly in Welland, Pelham, Grimsby, Lincoln, and west St. Catharines. If you bought a new home with APS signed on or after February 1, 2021, Tarion's new-home warranty may include coverage of up to $50,000 for radon mitigation, within a 7-year window. Meeting qualification criteria does not guarantee a claim will be approved. See our Tarion Radon Warranty Claim Guide.
Real estate & disclosure in Ontario
Ontario does not require radon disclosure on the standard SPIS, but the doctrine of latent defects (under common law and Ontario case law including Sevidal v. Chopra) generally creates an obligation to disclose known material latent defects. A confirmed elevated radon test is generally the kind of information a court might consider material — consult an Ontario real estate lawyer for any specific transaction.
For the full real-estate playbook, see Radon and Real Estate in Canada.
Renters in Niagara
Ontario's Residential Tenancies Act, 2006 generally requires landlords to maintain rental units in a "good state of repair and fit for habitation." Niagara renters — including students near Brock University and Niagara College — should consider testing their unit, especially in basement apartments. See our Radon for Canadian Renters (2026) guide.
FAQ — Niagara-specific questions
Is radon a real concern in St. Catharines and Niagara? Yes. The Niagara Escarpment introduces localized geological variation that can produce elevated indoor radon in specific homes. The only way to know your specific home's level is to test.
What's the action level for radon in Niagara? 200 Bq/m³ — the Health Canada residential guideline.
How do I test my Niagara home? Use a 3-month (≥91-day) long-term alpha-track test from a C-NRPP-recognized lab, placed in the lowest lived-in level during the heating season. Cost: $89 all-in for a RadonTest.ca kit.
How much does radon mitigation cost in Niagara? Typical: $2,500–$4,500 for standard sub-slab depressurization (SSD).
Does proximity to the Niagara Escarpment affect radon? The Niagara Escarpment includes localized geological variation that can produce elevated radon in escarpment-adjacent neighbourhoods. The only way to know your specific home's level is to test.
Does Tarion cover radon mitigation for new homes in Niagara? Up to $50,000 for qualifying new builds with APS signed on or after February 1, 2021, within a 7-year window. Meeting qualification criteria does not guarantee claim approval. See our Tarion claim guide.
Is there a Niagara Region Public Health radon program? Niagara Region Public Health has historically supported radon awareness programming. Check directly for current offerings.
Can I use the Lungs Matter grant in Niagara? The Canadian Lung Association's Lungs Matter program offers up to $1,500 toward radon mitigation for eligible Canadian homeowners. Verify eligibility directly.
Should I retest after mitigation? Yes — Health Canada generally recommends retesting after mitigation and after major renovations.
What if my Niagara landlord won't address elevated radon? Document everything in writing and consider escalating to the Ontario Landlord and Tenant Board.
Order your test kit
Order your $89 all-in long-term test kit →
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.
Ships across Niagara Region including St. Catharines, Niagara Falls, Welland, Thorold, Niagara-on-the-Lake, Pelham, Lincoln, Grimsby, and surrounding municipalities.
Important disclaimers
Not medical, legal, or warranty advice. Consult qualified Ontario professionals for any specific transaction, claim, or installation decision.
Statistics and citations. Ontario radon prevalence figures are drawn from Health Canada's Cross-Canada Survey of Radon Concentrations in Homes (2012). Figures cited reflect the sources as of May 2026.
Local data. The Niagara Region's escarpment geology adds localized variation; home-to-home variability is large. Test your specific home.
Mitigation cost. The $2,500–$4,500 Canadian residential SSD cost range reflects typical Canadian pricing as of 2026. Actual quoted prices vary.
Tarion qualification hedge. Coverage depends on APS date, test type and timing, professional qualifications, and other Tarion-specific rules. Meeting the qualification criteria does not guarantee a claim will be approved.
Lungs Matter grant. Eligibility, grant amounts, and program availability may change. Verify directly at lung.ca before relying on the program.
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
Niagara/Ontario-specific
Health Canada / national
- Health Canada — Radon: About
- Cross-Canada Survey of Radon Concentrations in Homes (2012)
- Guide for Radon Measurements in Residential Dwellings
- Canadian Cancer Society — Radon
- Canadian Lung Association — Lungs Matter
- C-NRPP — Find a Professional
- CARST
- Take Action on Radon
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