The search for "acceptable radon level" appears on the site, and the English equivalent "safe radon levels in canada" has about 480 searches per month in Canada. The site ranks around 35th place for this phrase. Here are the two thresholds that really matter, and what they don’t say.
200 Bq/m³: Health Canada Threshold
Health Canada recommends taking action when the concentration exceeds 200 becquerels per cubic meter (Bq/m³), measured over a sufficiently long period. This is not a license to remain at 199. It is the threshold at which correction is indicated.
100 Bq/m³: WHO Reference Level
The World Health Organization uses 100 Bq/m³ as a reference level. Many homeowners aim to reduce levels to this figure after mitigation work. Gaz Radon Québec’s guarantee does not promise a result below 100 Bq/m³ in all buildings. The follow-up conditions are written in the estimate, before the work.
The Threshold Means Nothing Without Test Duration
A reading of a few hours varies with the weather. The 4-day test (74.72 $ taxes included (detector 39.99 $ + return and laboratory 25 $ + taxes)) is used for screening. The 91-day dosimeter (74.72 $ taxes included (detector 39.99 $ + return and laboratory 25 $ + taxes)) measures during the normal life of the house. It is this second figure that is compared to 200 Bq/m³.
Above 200 Bq/m³
The usual correction is sub-slab depressurization: a pipe and a fan that draw gas from under the foundation and expel it outside. The standard installation costs 2,799.99 $ + taxes, price confirmed before work, with a 5% guarantee under the written estimate of a competitor for a comparable installation. Requests are made on the mitigation page or at 418-681-7964.