Flood zone · Guide · 2026
The new maps, the four classes, what the law still allows, and the three checks that decide whether a house near the water can be bought, insured and financed.
Since 1 March 2026, Quebec manages flood zones with a modernized regulatory framework and new-generation maps, published progressively on zonesinondables.mrnf.gouv.qc.ca, which replace the 0-20 and 20-100 year zones with four intensity classes (low, moderate, high, very high) by probability of flooding over 25 years and water depth. New construction is prohibited in the moderate to very high classes and permitted under conditions in the low class; rebuilding after a disaster is permitted under conditions; maintenance remains permitted. For the buyer, three checks: the map for the address, insurability (the overland flood endorsement has existed since 2017, about 50% of policyholders have it, and the insurer can refuse it by risk) and financing (Desjardins no longer lends in high-current zones since February 2024). For the seller, any past flood is declared in the OACIQ form. The new maps would raise the number of homes in at-risk zones from 22,000 to 77,000.
The modernized regulatory framework for water environments has replaced the transitional regime since 1 March 2026. It rests on new-generation maps, published progressively since spring 2026 on the zonesinondables.mrnf.gouv.qc.ca portal, which sort every flood zone into four intensity classes, by probability of flooding over 25 years and water depth, instead of the old 0-20 year and 20-100 year zones. They add river mobility zones, short term (50-year horizon) and long term (100 years and more), and they are reviewed at least every 10 years. Until a city has its new map, the maps in force at the municipality or the MRC apply, with the modernized framework's rules.
| Intensity class | What it means (probability over 25 years and water depth) |
|---|---|
| Very high | more than a 70% probability of being flooded at least once in 25 years, with more than 30 cm of water |
| High | between 70% and 20% probability with 30 to 60 cm of water, or more frequent floods with less water |
| Moderate | between 20% and 7% probability with more than 60 cm of water |
| Low | between 20% and 7% probability with 0 to 30 cm of water |
Why it matters: the new maps would raise the number of homes in at-risk zones from 22,000 to 77,000, according to figures announced in 2025 (La Presse, 5 June 2026). A house that was not in a zone yesterday may be tomorrow, and the reverse when a dike is recognized. The 2017 to 2019 floods cost more than a billion dollars and affected thousands of properties (release of 12 June 2025).
The detail by situation is in our pages renovating or rebuilding in a flood zone and reading the flood zone map.
The seller declares any past flood in the mandatory form Declarations by the seller of the immovable; the seller's broker makes sure the facts and proof (invoices, photos) appear in it; a flood between acceptance of the promise to purchase and the deed requires amending the declarations and informing the buyer. A flooded house restored with invoices and photos sells; a house whose flood is hidden gets sued. Our page selling a house in a flood zone gives the method, and seller's declaration and flooding the detail of the form.
Quebec's general compensation program covers a principal residence up to $385,000, immunisation included; when damage reaches 50% of the replacement cost or $162,500, immunisation becomes mandatory, or the departure allowance to demolish. Immunisation means raising the building above the flood level or rebuilding the foundations, with work completed within 18 months and the choice returned within 30 days; an immunised residence is no longer eligible for future flood assistance (rule since 10 April 2019). A buyer must ask whether the house has already received that assistance.
The situation changes from one river to the next: Gatineau, Laval, Pierrefonds-Roxboro, Deux-Montagnes and Sainte-Marthe-sur-le-Lac, Vaudreuil-Dorion and Rigaud, Saint-Jean-sur-Richelieu. The hub flood zones by city gathers them.
On the government's interactive map (zonesinondables.mrnf.gouv.qc.ca) for territories with a new-generation map, otherwise at your municipality or MRC. The certificate of location and the seller's declaration complete the answer for a house for sale.
Yes, but three things decide: the zone's intensity class (what you will be able to do there), insurability (the endorsement can be refused by risk) and financing (Desjardins no longer lends in high-current zones since February 2024). The price must reflect all three.
A new residence is prohibited in the moderate, high or very high class and in the high-current zone; it is permitted under conditions in the low class and in already built-up sectors. Rebuilding after a disaster is permitted under conditions, and a heavily damaged house must be immunised or demolished.
Sources read on 15 September 2026: Québec.ca (regulatory framework for water environments in force 1 March 2026, interpretation of new-generation maps, work in flood zones, disaster financial assistance and immunisation), the zonesinondables.mrnf.gouv.qc.ca portal, Insurance Bureau of Canada (spring floods and insurance), OACIQ (transaction on a flooded property), Communauté métropolitaine de Montréal, Radio-Canada (Desjardins, February 2024), La Presse (insurance guide, 5 June 2026). Informational page: your municipality, insurer and lender decide for your address.
The Loaa & Manseur team, led by Lotfi Manseur and Loaa Al Daow, is the number 1 team at RE/MAX Platine in 2024 and 2025, 6th RE/MAX team in Quebec, 15th in Canada and in the global top 50 of large residential teams according to the official RE/MAX ranking, computed on actual transactions. Its Google profile counts more than 220 reviews with a 4.9 rating. Its offices are at 55 avenue de l'Équinoxe in Brossard, one bridge from the island, and every broker's licence can be checked in the OACIQ public register. Three things to verify yourself before calling us, and to demand of any other broker.
Also available in French: version française de ce guide.
Published September 7, 2026 by the Loaa & Manseur team, the number 1 team at RE/MAX Platine in 2024 and 2025, 6th RE/MAX team in Quebec, 15th in Canada and in the global top 50 according to the official RE/MAX ranking. Tell us about your project.
Équipe no 1 de RE/MAX Platine en 2024 et en 2025, 6e au Québec, 15e au Canada et dans le top 50 mondial au classement officiel RE/MAX. Réponse en moins de 24 heures, sept jours sur sept.