What it is
Radon forms naturally as uranium in soil and rock breaks down. It moves into homes through cracks, gaps and openings in contact with the ground, and it can build up indoors, especially in basements and on lower floors. Long-term exposure to high levels increases the risk of lung cancer. Health Canada’s guideline is 200 becquerels per cubic metre (200 Bq/m³), based on the average over the year.
Radon in BC
Elevated levels are found throughout most of the province. They’re typically higher in the Interior and the North, but levels vary from house to house, so a test is the only way to know. HealthLinkBC encourages everyone to test. Renovations and energy upgrades that change how a house is sealed are a good reason to test again.
How to test
- Use a long-term test of at least three months (91 days), ideally through the fall and winter heating season.
- Place the detector on the lowest level where someone spends more than four hours a day.
- Use a long-term test kit, or have a C-NRPP-certified radon professional do the measurement.
Follow the kit’s instructions on placement and on returning it to the lab. Short tests of a few days aren’t a sound basis for decisions, so testing usually happens after possession rather than inside a subject period.
If the level is high
Health Canada’s guidance is to reduce radon within a year when a long-term test shows more than 200 Bq/m³, and sooner if the level is higher. The usual fix draws soil gas from under the floor with a pipe and fan and vents it outside. Have it installed by a C-NRPP-certified radon professional, and retest afterwards. Health Canada also recommends retesting a home with a mitigation system every five years.
What our inspection covers
A home inspection doesn’t test for radon, and no visual inspection can tell you a home’s radon level. We note features that matter if you test later, such as an exposed earth floor in a crawlspace, an open sump or gaps where pipes pass through the slab.
Questions about testing after you move in are welcome. Book an inspection and ask us on the day.
Reviewed October 26, 2026 by Nick Hawley, Watch House Inspections. General information, not advice about a particular home.