Windsor-Essex
Radon testing and mitigation in Windsor, Ontario
Windsor is one of the few places in our service area where the local health unit has published its own radon study. Here’s what’s known about radon in Windsor, and how to find out about your home.
- Region
- Windsor-Essex
- Population
- about 230,000
- Public health
- Windsor-Essex County Health Unit
- Local factors
- 5 reasons to test
Is radon a problem in Windsor?
Radon can exceed Health Canada’s 200 Bq/m³ guideline in any Windsor home. The Windsor-Essex County Health Unit’s 2015 to 2018 study found about 6% of City of Windsor homes above the guideline, against 18% in Essex County. Across Ontario, about 1 in 8 homes tested at or above the guideline in the 2024 national survey. Locally, cracking clay soils, shallow or fractured bedrock and century-home foundations are reasons to test. A 91-day test is the only way to know your home’s level.
Radon in Windsor
Windsor is one of the few places in our service area where the local health unit has published its own radon study. The Windsor-Essex County Health Unit’s Radon: Know Your Level project ran from 2015 to 2018, and about 6% of the City of Windsor homes tested came in above Health Canada’s 200 Bq/m³ guideline. That is lower than neighbouring Essex County, and it still means a real share of Windsor basements need a fix.
The ground under Windsor
Windsor sits on the flat Detroit River lake plain: glacial lake clay and silt over till, with limestone and dolostone bedrock not far down. Clay slows soil gas, but it shrinks and cracks in dry summers, and the stone and gravel bed around a foundation and under a slab give gas a direct route into the house.
Windsor’s homes
Brick houses from the 1920s to the 1960s fill Walkerville, Olde Riverside, Sandwich Town, Remington Park and South Windsor, most with full basements, floor drains and sump pits. Newer homes in South Windsor and Forest Glade are larger and tighter. Basement suites and finished lower levels put people in the part of the house where radon is usually highest.
What the data says
Of City of Windsor homes tested in the Windsor-Essex County Health Unit’s 2015 to 2018 study were above the 200 Bq/m³ guideline. Essex County came in at 18%, and the two combined at 11%.Source: Windsor-Essex County Health Unit — Radon: Know Your Level, 2015–2018 report
Of homes tested in the Windsor-Essex health unit area were at or above 200 Bq/m³ in the Health Canada survey data tabulated by Cancer Care Ontario (2009 to 2013).Source: Cancer Care Ontario — Risk of Residential Radon Exposure Varies Geographically (results by public health unit, Health Canada survey data 2009–2013)
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)
Local results
Building a real radon picture for Windsor
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.
Windsor: collecting results. Already tested? Check your number and share it anonymously when you book.
Local factors
What can push radon up in Windsor
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.
Shallow or fractured bedrock
Where rock sits close to the surface, as on the Niagara Escarpment or the limestone plains near Lake Erie, joints and fractures can act as pipelines that carry soil gas toward foundations.
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.
New, airtight construction
Canadian research shows newer homes have tended to test higher than older ones. Bigger, taller and tighter homes create a stronger stack effect that draws soil gas in through the slab.
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
Windsor neighbourhoods and nearby communities
- Walkerville
- Olde Riverside
- Sandwich Town
- Riverside
- South Windsor
- Forest Glade
- Remington Park
- Devonshire Heights
- Roseland
- Downtown Windsor
- Ojibway
- East Windsor
Nearby: Radon in Leamington · Radon in Chatham
How it works
From test to fix
- Book
Tell us about your Windsor 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 Windsor: FAQ
Is radon a problem in Windsor?
Radon can exceed Health Canada’s 200 Bq/m³ guideline in any Windsor home. The Windsor-Essex County Health Unit’s 2015 to 2018 study found about 6% of City of Windsor homes above the guideline, against 18% in Essex County. Across Ontario, about 1 in 8 homes tested at or above the guideline in the 2024 national survey. Locally, cracking clay soils, shallow or fractured bedrock and century-home foundations are reasons to test. A 91-day test is the only way to know your home’s level.
What did the Windsor-Essex health unit find about radon?
The Windsor-Essex County Health Unit’s Radon: Know Your Level study (2015 to 2018) found about 11% of homes tested above 200 Bq/m³ overall: 6% in the City of Windsor and 18% in Essex County. A study average can’t tell you about one house, which is why we test the house.
My Windsor basement has a sump pit and floor drain. Does that matter?
Yes. Open sump pits, floor drains and cracks where the slab meets the wall are common entry points for soil gas. Sealing helps, but a sub-slab system that pulls gas from under the slab and vents it above the roof is what Health Canada’s guidance relies on to bring a high result down.
Do you offer radon testing and mitigation in Windsor?
Yes. We test and mitigate homes throughout Windsor, including Walkerville, Olde Riverside, Sandwich Town, Riverside, South Windsor and nearby. Call (226) 271-4667 or book online.
Radon is fixable. First, know your number.
Serving Windsor, Leamington and Chatham.