This content is intended for the public covered by the exceptions of the Charter of the French language and its regulations. If you read on, you confirm that you fall within one of these exceptions.
Flooding and spring freshets
The risk of flooding is persistent on an island bordered by two major rivers. Find out how to prepare.
Seasonal Monitoring
Update
May 6, 2025, 9:00 AM
Alert Level
Alert
Situation Status
- Rise Water flow and Levels of the Prairies and Mille Îles Rivers.
- Increased Monitoring by Municipal Teams.
- Preventive measure: installation of a dike on Riviera Street (Laval-Ouest) starting May 1
Advice to the Public
- Review flood preparedness tips.
- Learn about financial assistance from the Government of Québec for implementing temporary preventive measures.
The City will provide updates if the situation worsens.
Check this page regularly for updates on the situation and instructions in case of flood risk.
When and where is there a risk of flooding?
Certain areas are more prone to flooding, particularly those near rivers. Flooding often occurs during the spring freshet between March 15 and May 15. The flood risk is always higher in the presence of violent weather events, including high winds, storms, tornados and hurricanes.
There are several ways to protect yourself and mitigate the damages caused by flooding:
- Contact your insurer to check your coverage in the event of backflow, groundwater infiltration, and a river overflowing.
- Check to make sure that your sump pump is working properly and your sewer check valve is watertight.
- Create a slight slope so that stormwater drains away from your foundation.
- Favour landscaping and plants that promote water absorption, contrary to paved surfaces.
- If your home is on a floodplain: During the spring freshet, arrange your basement in such a way that objects of value are high off the floor, or bring them up to ground level, if possible.
- Safely store objects that could be swept away by the current (garden furniture, dock, etc.).
- Prepare your family safety plan https://www.laval.ca/Pages/Fr/Citoyens/preparation-sinistre.aspxand a ready-to-go emergency bag in the event that you must evacuate. Also keep on hand all the items you need to ensure your autonomy for a minimum period of 72 hours.
- Find out in advance where you can find refuge (with family, friends, etc.).
- Protect building entrances (windows, doors, garage, etc.) by creating a dike (low wall) using sandbags. How to build a low wall (PDF, 558 KB – in French) [document externe].
- Clear any obstacles to the evaluation of water through the sewer inlets, gutters and drains (ice, branches, leaves, etc.).
- Move everything that you can up to the floors: furniture, electrical appliances, clothing, photos, etc.
- Take detailed photographs of your property and property items before any disaster strikes. Keep the photos in a secure cloud storage service or on a USB key kept outside of your home.
- If your home is located on a floodplain, you can avoid or limit the damage by calling upon an expert.
- The following professionals will be able to help you:
- Landscape architect
- Engineer
- Biologist
- Contact 911 to report a situation in which the life, health and safety of a person is threatened.
- If the situation is serious, leave your home before the streets become impassable. In doing so, you won’t have to drive through floodwaters.
- Shut off the power if water begins to rise close to electrical components. When cutting the power, make sure your feet are on a dry surface and use a wooden stick to cut the power and thus avoid contact with the electrical panel. If necessary, contact a master electrician.
- Shut off the main natural gas inlet as well as the valves on propane and fuel oil tanks. Make sure that they are solidly anchored to the ground if there is a risk that they will be flooded.
- Electrical installations that come into contact with water may pose a risk of electrocution or fire. Immediately notify Hydro-Québec, which will cut the power.
- Stay away from downed power lines and wires, even if there is a power outage.
- If water backs up from the floor drain or the sewer pipes, block the inlets with a cloth.
- You can install pumps to evacuate the water from your home or the edge of your sandbag dike. To avoid carbon monoxide poisoning, never use a motorized pump, generator or any other gas-powered device (propane, fuel, diesel) inside your home.
- If you don’t own a pair of tall boots, avoid walking in floodwaters, as they can be dangerous and contaminated.
- Comply with the safety guidelines issued by public authorities.
Concerned about your health?
If you suspect that mould or a sanitation problem is adversely affecting your health, please contact the Centre intégré de santé et de services sociaux (CISSS) de Laval or contact 811.
When to contact 311?
- When your home is flooded
- When you leave your home
- When you return home
- To request information
- Do not consume the tap water until you receive authorization from the city. When first turning on the tap, let the water run for a few minutes. Check to make sure that the well water is safe before drinking it.
- Disinfect objects, foods and medications that come into contact with flood waters.
- Have the electrical installations and heating appliances checked by a master electrician before reconnecting them.
- Watch for the presence of mould. If necessary, call upon a specialized company.
- Draw up an inventory of the damages and take photos clearly demonstrating the height that the water reached, then inform your insurer and the City of Laval.
- Quickly demolish and decontaminate the parts of your house that have been flooded in order to avoid mould. If necessary, call upon a specialized company.
- Contact 211 to receive help from community-based organizations, based on your needs.
- Document all the steps that you take and keep receipts for cleaning and repair work for your insurance records.
- Don’t forget to regularly update your photos and store them in the cloud or on a USB key, particularly after renovating or purchasing property items of high value.
1. Rapidly dry
- Start drying as quickly as possible, ideally within 24 to 48 hours of the flood, to prevent mould.
2. Ventilate and dehumidify
- Open the doors and windows to allow air to circulate.
- Use fans and dehumidifiers to speed up the drying process.
- Allow air to circulate well in all the affected rooms and areas.
3. Porous materials
- Remove and throw out porous materials that cannot be completely dried, such as carpets, upholstered furniture, gypsum and insulation.
- Carefully clean objects that you wish to keep and dry them thoroughly.
4. Wood and hard surfaces
- Clean and disinfect all hard surfaces with an odourless detergent and hot water.
- Slowly dry wooden furniture to avoid cracking and warping.
5. Electrical appliances
- Have a professional check your electrical appliances before using them again.
- Replace appliances that were submerged if they are beyond repair or if repairing them is too costly.
6. Documents and items of value
- Freeze important documents and soiled books to preserve them until you are able to dry them properly.
- Consult a professional restorer for water-damaged items of value.
7. Monitoring and follow-up
- Check for signs of mould (mouldy smell, spotting on the walls or ceilings) during and after the drying process.
- Keep the relative humidity lower than 50% inside the house after cleaning to prevent mould.
8. Safety
- Always wear the proper personal protective equipment when cleaning and drying (gloves, mask, waterproof boots).
- Make sure the power is turned off in flooded areas before starting work.
For further information, please view the brochure for flood victims issued by the Government of Canada.
How to validate building sanitation and safety
After a water infiltration into a home, it is important to act quickly to limit the formation of mould, as its dispersal into the air can lead to health problems.
Be careful for the:
– Smell of mould, earth or alcohol.
– Signs of spotting (green or black) on the walls or ceilings, in the cupboards or behind items that have not been removed.
View the document entitled What to do in your house after a flood (in French)
Learn about finding and eliminating mould from your home
Information about mould
Rebuilding after a flood
- The owner of a structure that is damaged must take the necessary measures, without delay, to secure the premises and avoid mould.
- No construction permit is required to remove finishing materials (e.g., floating floors or door frames) affected by flooding.
- Some work, such as painting, does not require a permit, since it is considered maintenance work.
- If you undertake major work that affects the structure of your home, please contact the Service de l’urbanisme to submit an application for a renovation or transfer permit.
How waterways are monitored
Want to find out how waterways are monitored? The City of Laval has installed 14 telemetric stations at strategic locations around Île Jésus. These stations monitor water levels and issue alerts.
A camera was also installed to monitor certain situations. These data are not available in real time, as they must first be validated and interpreted. To improve monitoring, the City of Laval also has access to government soundings.
The following tools can also be used to monitor water flow:
- Forecasts from the Ministère de l’Environnement, de la lutte contre les changements climatiques, de la faune et des parcs du Québec.
- Active flooding in the last 72 hours from Natural Resources Canada.
