Formula or decision rule
test duration = end timestamp − start timestamp; decision = valid result compared with current jurisdiction guideline- For Canada, the cited long-term measurement is at least 91 days.
- Health Canada’s guideline is 200 Bq/m³ as an annual average.
- For U.S. decisions, use the current EPA test and action instructions shown with the result.
Radon test record
| Field | United States | Canada |
|---|---|---|
| Why test? | testing is the only way to know | measure the dwelling |
| Duration | follow EPA/device test instructions | long term, at least 91 days |
| Comparison | current EPA action guidance | 200 Bq/m³ annual average guideline |
| Record | device, placement, dates, result | device, placement, dates, result |
Work through the project
Choose the jurisdiction process
Open the current EPA or Health Canada guidance and use a device and placement method that meets it.
Protect test validity
Record exact start/end times, location, device identifier, relevant conditions, and any disturbance.
Act on the valid result
Compare only after checking validity, then follow the jurisdiction’s confirmation or mitigation steps.
Safety and scope
- Do not use a calculator, map, or neighboring result as a substitute for testing the home.
- Qualified radon professionals can help with testing questions and mitigation.
Sources and scope
Source links reviewed July 16, 2026. A review date is not the document's publication date.
- U.S. Environmental Protection Agency: RadonUnited States · government guide
Test results and mitigation decisions should follow current EPA instructions and device directions.
- Health Canada: Government of Canada Radon GuidelineCanada · government guide
Mitigation urgency depends on the long-term result; follow current Health Canada guidance.
- Health Canada: Guide for Radon Measurements in Residential DwellingsCanada · government guide
The guide calls for a minimum 91-day long-term measurement for a valid annual estimate.