Test long enough
Health Canada's 2026 guidance calls for a long-term test of at least 91 days, ideally with at least 91 days during the heating season. Longer tests can better represent the annual average.
Radon in Niagara: what should you do next?
Whether you're finishing a basement, buying a home or checking a radon reading, the right next step depends on how and where your home was tested.
Is radon a concern where you live in Niagara?
A radon reading from another property cannot tell you what is happening inside your home. Levels can vary significantly between neighbouring houses, even on the same street. Testing the spaces your household regularly uses is more useful than relying on a nearby result or a regional map.
Choose the lived-in level
Test the lowest level where people regularly spend time, such as a basement family room, bedroom, office or playroom. An unfinished storage basement may not be the right test location.
Use the long-term average
Canada's radon guideline is 200 Bq/m³. A single day's reading from a home monitor cannot establish the average exposure used for a mitigation decision.
Should you test in the basement or on the main floor?
If your basement is a regular family room or a child's playroom, that level may be the right place to measure. If the basement is used only for storage and laundry, a regularly occupied room on the main floor is usually more appropriate.
Place the detector away from windows, vents, bathrooms, kitchens and other locations where airflow or moisture could distort the result. Always follow the specific detector's placement instructions.
What if you already have readings from a monitor?
A few unusually high hours during a cold week are worth noticing, but they are not the same as a representative long-term average. If a test lasted fewer than 91 days, it may not be suitable for deciding whether the home needs mitigation.
A result below 200 Bq/m³ from a test with less than 91 days during the heating season may underestimate the annual level. Health Canada recommends retesting during the next heating season in that situation. An elevated long-term result should not be dismissed while waiting for another season.
What does your radon number mean?
Compare a representative long-term result with Canada's 200 Bq/m³ guideline. The higher the measured level, the more important it is to take action promptly.
Below 200 Bq/m³
The result is below the Canadian guideline, although there is no completely risk-free radon level. Keep a record of where and how the measurement was taken. Consider retesting after changes to the home's structure, basement use or ventilation.
Above 200 Bq/m³
Health Canada's updated guidance recommends reducing a confirmed elevated long-term level within one year, acting sooner for higher levels. A certified radon mitigation professional can assess suitable solutions for the building.
Near the guideline or unsure whether the test was long enough?Ask about your radon result and include the test duration and room where the detector was placed.
Three property decisions worth thinking through.
These examples show how testing questions can arise at different stages of homeownership. They are illustrative, not accounts of completed customer projects.
Finishing a basement
Planning a basement bedroom, office or family room? Consider where people will spend time after the renovation. Structural or ventilation changes may warrant retesting during the next heating season.
Buying or selling a home
A purchase or sale can move faster than a 91-day test. Do not mistake a short-term monitor reading for a completed long-term measurement. Discuss available results, timing and next steps with your real estate professional.
Moving into a new build
A radon rough-in can make later mitigation easier, but does not prove the indoor radon level is low. Plan to test during the first heating season after moving in and check applicable requirements with your municipality's building department.
How does a radon system fit your home?
The design depends on the foundation, available space, soil-gas entry pathways and safe exterior exhaust routing. A common method draws soil gas from beneath the foundation through sealed piping with a fan and discharges it outside.
Rather than assuming a particular fan position or pipe route fits every house, ask how a proposed installation would affect the building and how performance will be checked after installation.
Why local building details matter.
The right approach for a finished basement may differ from planning a radon rough-in during new construction. Building requirements and permit questions should be confirmed with the relevant building department; rules for new construction should not be assumed to apply to every existing home.
After mitigation, follow-up measurements are important to confirm that the system is doing its job, including a long-term test during the next heating season.
What information is useful to share?
You do not need a complete technical report to get started. These details help frame a useful testing or mitigation conversation.
- The property location and type, including whether the basement is regularly used.
- The measured radon level and units, if you have a result.
- The device type, test duration, and room or floor where it was placed.
- Whether you are renovating, purchasing, moving into a new build, or reviewing an existing result.
Need a clear next step for your Niagara home?
Request a radon test, share an existing result or ask about mitigation options. We'll follow up by phone or email.