Flood zone · Châteauguay · 2026
The map in force in Châteauguay, what the City put in place, what the 2026 framework allows, and the checklist for a house near the Châteauguay River and Lac Saint-Louis.
Flood zone in Châteauguay in 2026: The map in force is schedule F (flood zones) of the zoning by-law, updated on 1 May 2017, with the Châteauguay River's high-velocity zone. Since 30 June 2025, land surveyors mandated by the Ministère des Ressources naturelles et des Forêts have been characterizing buildings in certain sectors (door threshold elevation, height of the lowest opening, number of storeys) under the flood protection plan for the territory; they do not enter homes. The modernized regulatory framework of 1 March 2026 applies: new residence prohibited in the moderate, high and very high classes and in the high-current zone, permitted under conditions in the low class; rebuilding under conditions; maintenance permitted. Before buying near the Châteauguay River and Lac Saint-Louis: the written class for the address, an insurance quote with the flood endorsement, a lender's position (Desjardins no longer lends in high-current zones since February 2024), the certificate of location and the seller's declaration. Sources read on 16 September 2026.
The map in force is schedule F (flood zones) of the zoning by-law, updated on 1 May 2017, with the Châteauguay River's high-velocity zone. The CMM's preliminary map, unveiled in 2024, would raise the number of homes in a flood zone in Châteauguay from about 700 to about 1,100, notably because it accounts for the Salaberry Nord and D'Youville dikes (Le Soleil de Châteauguay, 23 October 2024); it is not yet in force.
Since 30 June 2025, land surveyors mandated by the Ministère des Ressources naturelles et des Forêts have been characterizing buildings in certain sectors (door threshold elevation, height of the lowest opening, number of storeys) under the flood protection plan for the territory; they do not enter homes. The City runs an Info-rivière service with its own hydrometric station: as of 11 March 2026, ice evacuation was complete and the level posed no risk.
Before buying, check Info-rivière and the Crues Grand Montréal site (72-hour forecasts), then check schedule F for the address. The City's Inondation page details the protections required or recommended: 200 mm clearance under basement windows or window wells, backwater valve on the drain, sump pit and pump. Every permit goes through the inspection and permits division (by-law Z-3400). The modernized framework's rules apply everywhere: new residence prohibited in the moderate to very high classes and in the high-current zone, rebuilding under conditions, maintenance permitted; the detail is in renovating or rebuilding in a flood zone.
The written class, the certificate, proof of restoration or immunisation, an insurance quote for the address and a lender's position: that is the file that defends the price, described in selling a house in a flood zone. A broker from the team who knows Châteauguay builds it before listing.
The map in force is schedule F (flood zones) of the zoning by-law, updated on 1 May 2017, with the Châteauguay River's high-velocity zone. A recent certificate of location and the seller's declaration complete the answer.
A new residence is prohibited in the moderate to very high classes and in the high-current zone, permitted under conditions in the low class; rebuilding after a disaster is permitted under conditions, with a municipal permit and often immunisation.
By class and by the house's history: the flood endorsement can be offered or refused by the insurer, and Desjardins no longer lends in high-current zones since February 2024; other lenders judge case by case.
Sources: ville.chateauguay.qc.ca, pages Info-rivière, Inondation, « Zones inondables : des travaux de caractérisation en cours » (30 juin 2025) et annexe F du zonage; Le Soleil de Châteauguay, 23 octobre 2024, lus le 16 septembre 2026; Québec.ca (regulatory framework of 1 March 2026). Informational page: the City decides for your address.
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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.