Flood zones: check an address in Montréal, Québec, Laval, Gatineau, Longueuil or Sherbrooke
The Quebec government publishes a database of flood zones. The high-velocity zone has at least a 1-in-20 chance of flooding each year (0–20 year); the low-velocity zone, between 1 in 20 and 1 in 100 (20–100 year). Since 2026 new maps by risk level are being published city by city.
What it changes
- Building and renovating: extending, rebuilding or adding a dwelling is regulated, sometimes forbidden in the high-velocity zone.
- Insurance: flood cover may cost more or be refused; get a quote before you remove your conditions.
- Resale: buyers and lenders look at the same maps.
Outside a zone does not mean no water risk: sewer back-up is a separate risk, especially with a finished basement. More about flood zones · To check an address, use the address search.
General information, not legal or professional advice.
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