Niagara Region
Radon testing and mitigation in St. Catharines, Ontario
St. Catharines is Niagara’s largest city, with neighbourhoods from heritage Port Dalhousie to post-war Grantham and the hillside homes around Brock University. Here’s what’s known about radon in St. Catharines, and how to find out about your home.
- Region
- Niagara Region
- Population
- about 137,000
- Public health
- Niagara Region Public Health
- Local factors
- 4 reasons to test
Is radon a problem in St. Catharines?
Radon can exceed Health Canada’s 200 Bq/m³ guideline in any St. Catharines home. No published local data rules any neighbourhood in or out. Across Ontario, about 1 in 8 homes tested at or above the guideline in the 2024 national survey. Locally, cracking clay soils, sandy or gravelly soils and century-home foundations are reasons to test. A 91-day test is the only way to know your home’s level.
Radon in St. Catharines
St. Catharines is Niagara’s largest city, with neighbourhoods from heritage Port Dalhousie to post-war Grantham and the hillside homes around Brock University. A lot of the housing dates from the 1940s to 1970s, often with basements that have since been finished.
The ground under St. Catharines
The city sits on the Iroquois Plain: glacial lake sands, silts and clays over red shale, with the Escarpment rising at its southern edge. Twelve Mile Creek and the Welland Canal cut through the city. Sandy beach ridges near the lake and clay further inland give quite different soil conditions across short distances.
St. Catharines’s homes
Post-war bungalows and storey-and-a-halfs often have floor drains, sumps and block foundations. Port Dalhousie and Old Glenridge have older homes still. Near Brock, many homes are rentals with basement bedrooms, where radon exposure can be highest.
What the data says
Ontario homes at or above Health Canada’s 200 Bq/m³ guideline in the 2024 Cross-Canada Survey, more than double the share found a decade earlier.Source: Cross-Canada Survey of Radon Exposure in the Residential Buildings of Urban and Rural Communities (2024)
Roughly how many homes per health region the first national survey (2009–2011) could test. Too few to clear any neighbourhood, which is why public maps can’t tell you about your house.Source: Health Canada — Cross-Canada Survey of Radon Concentrations in Homes, Final Report (2012)
Higher average radon exposure for rural residents than urban residents in a 2024 national study of 42,051 homes, mostly linked to drilled wells.Source: Goodarzi et al., Scientific Reports (2024) — rural communities and drilled-well annuli
Local results
Building a real radon picture for St. Catharines
Public radon data for Southern Ontario towns is thin. The national surveys tested only a handful of homes per area. So we’re building our own: anonymized long-term results from homes we test, published by area once there are at least 30, so no single home can be identified and small samples can’t mislead.
St. Catharines: collecting results. Already tested? Check your number and share it anonymously when you book.
Local factors
What can push radon up in St. Catharines
Not a prediction for any single home, just the reasons a test is worth it here.
Clay plains
Dense clay slows soil gas, but it cracks in dry spells. Gas then follows the easiest route: the gravel backfill, weeping tile and utility trenches that lead straight to a basement.
Sandy or gravelly soils
Sand and gravel let soil gas move freely and over longer distances. More of the radon formed in the ground can reach the air around your foundation instead of decaying in place.
Century homes
Fieldstone, rubble and early concrete foundations, earth-floor cellars and open sumps give radon many ways in. Older doesn’t mean safer: these homes still need a test.
Lived-in basements
Radon is usually highest on the lowest floor. Basement bedrooms, home offices and rental suites mean people spend hours a day where exposure is greatest.
Where we work
St. Catharines neighbourhoods and nearby communities
- Port Dalhousie
- Downtown
- Old Glenridge
- Western Hill
- Merritton
- Grantham
- Facer Street
- Secord Woods
Nearby: Radon in Thorold · Radon in NOTL · Radon in Beamsville · Radon in Welland
How it works
From test to fix
- Book
Tell us about your St. Catharines home. We reply within one business day.
- Test for 91+ days
A certified technician places long-term detectors on your lowest lived-in floor. You get an early reading at 2 weeks.
- Get your result
Lab-verified average, explained against Health Canada’s guideline.
- Fix it if it’s high
A sub-slab system designed for your foundation, at a fixed price, with results guaranteed.
Questions
Radon in St. Catharines: FAQ
Is radon a problem in St. Catharines?
Radon can exceed Health Canada’s 200 Bq/m³ guideline in any St. Catharines home. No published local data rules any neighbourhood in or out. Across Ontario, about 1 in 8 homes tested at or above the guideline in the 2024 national survey. Locally, cracking clay soils, sandy or gravelly soils and century-home foundations are reasons to test. A 91-day test is the only way to know your home’s level.
Should student rentals near Brock be tested for radon?
Yes. Basement bedrooms are common in student rentals, and Health Canada’s guideline applies anywhere someone spends more than four hours a day. A long-term test over the school year captures the heating season.
Is radon a problem in St. Catharines?
Homes above Health Canada’s guideline exist across Ontario, and nothing in the public data rules out St. Catharines. The only way to know about your home is a long-term test.
Do you offer radon testing and mitigation in St. Catharines?
Yes. We test and mitigate homes throughout St. Catharines, including Port Dalhousie, Downtown, Old Glenridge, Western Hill, Merritton and nearby. Call (226) 271-4667 or book online.
Radon is fixable. First, know your number.
Serving St. Catharines, Thorold, NOTL, Beamsville and Welland.