You placed the detector, waited 91+ days, and now you have a number. This guide explains how radon test results are reported and what Health Canada recommends at each level.
What Does Your Radon Number Mean?
Radon test results in Canada are measured in becquerels per cubic metre (Bq/m³). This unit represents the concentration of radon gas detected in your home's air over the testing period. A higher number means more radon was present.
Unlike a pass/fail test, radon results exist on a spectrum. According to Health Canada, there is no level of radon exposure considered completely risk-free ? but Health Canada has established a guideline to help homeowners make informed decisions.
The Health Canada Guideline: 200 Bq/m³
Health Canada's current guideline level is 200 Bq/m³. If your long-term radon test result is above this level, Health Canada recommends taking corrective action to reduce radon levels in your home.
It's worth noting that the World Health Organization (WHO) uses a lower reference level of 100 Bq/m³. Some homeowners choose to act at this lower threshold, particularly if there are smokers in the household. The World Health Organization notes that the combination of radon exposure and smoking significantly increases lung cancer risk.
Understanding Your Result Range
Below 100 Bq/m³: Your result is below both the WHO reference level and the Health Canada guideline. Health Canada does not recommend corrective action at this level, though Health Canada recommends retesting every 5 years or after major renovations, as radon levels can change over time.
100?199 Bq/m³: Your result is above the WHO reference level but below the Health Canada guideline. While no immediate action is required under Canadian guidelines, some homeowners choose to act earlier, particularly if anyone in the home smokes. Health Canada recommends retesting in 2–3 years.
200–599 Bq/m³: Your result exceeds the Health Canada guideline. Health Canada recommends hiring a C-NRPP certified radon mitigation professional to reduce levels. Health Canada recommends completing mitigation within 2 years.
600 Bq/m³ and above: Your result is significantly above the guideline. Health Canada recommends acting within 1 year to reduce radon levels. The C-NRPP directory can help you find a certified professional.
Long-Term vs. Short-Term Testing
Your test result is most reliable when it reflects a long-term measurement of at least 91 days. This is because radon levels in a home fluctuate daily and seasonally due to weather, soil conditions, and how the home is ventilated.
Short-term tests (2–7 days) can provide a quick snapshot, but Health Canada considers long-term testing during the heating season (October to April) to be the most reliable method for determining your home's annual average radon concentration.
At RadonTest.ca, every kit is designed for a minimum 91-day testing period using an alpha-track detector analysed by our ISO 17025 and C-NRPP certified lab partner, Lex Scientific ? ensuring your result reflects a reliable long-term average.
What Should You Do With Your Results?
If your result is below 200 Bq/m³, keep your report for your records and plan to retest in 5 years or after any major structural renovations.
If your result is above 200 Bq/m³, Health Canada recommends contacting a C-NRPP certified radon mitigation professional. The C-NRPP maintains a searchable directory of certified contractors across Canada. According to Health Canada, mitigation systems can typically reduce radon levels by more than 80%.
For process questions, visit our FAQ page. For mitigation options, use the C-NRPP directory.
Ready to test your home? Order your RadonTest.ca kit ? it includes the detector, lab analysis, email reminders, and results delivered with clear Health Canada context.