Can I test for radon during a conditional offer in Ottawa?

Not for a valid result. Health Canada says the minimum test length is 91 days for a valid estimate, with at least 91 days of the test during the heating season, and that short-term measurements are not appropriate for informing mitigation decisions. A test started during a condition period will not finish inside it unless the condition runs longer than three months.

So a short reading cannot serve as a pass or fail for the purchase. Health Canada's guideline is an annual average: take corrective action if the average annual radon level exceeds 200 Bq/m³ in the normal occupancy area.

What you can plan for instead:

• Health Canada recommends every home be tested, so a long-term test once you live in the house is the route to a valid number.
• Use a device on the C-NRPP list, in a normal occupancy area of the lowest lived-in level. Ottawa Public Health puts do-it-yourself long-term kits at $29 to $170.
• If the result is above 200 Bq/m³, Health Canada says individuals mitigate within 1 year, and points to a C-NRPP certified radon mitigation professional for the work.

Ottawa Public Health says radon concentrations vary a great deal within the City of Ottawa, making it difficult to predict radon levels in any one home, so a neighbour's result does not stand in for yours.

Whether radon belongs in your offer at all, and how, is a question for your agent or lawyer. Radon testing and mitigation as services are covered on ottawaabatement.com.

Ask your agent how the 91-day minimum fits your timeline before you write radon into an offer.