The silent danger of Montreal's low-lying areas. Is your house in a "low-lying area"?

Lavé-uni Montréal Blogger
Nov 11
3 min read

Images of Montreal streets transformed into rivers after a downpour are unlikely to fade anytime soon. Thousands of homeowners have discovered, to their dismay, that their house is located in a "basin," an area where water accumulates during heavy rainfall.

Understanding the risk: what is a basin?

A "basin" is a term that refers to a low-lying area of land where rainwater tends to collect. These areas, often unknown to homeowners, are particularly vulnerable to flooding during flash storms. The City of Montreal has even published a map identifying these areas, showing that nearly 27.5% of the territory is at risk . In some neighbourhoods, this figure rises to nearly 50% of properties .

Garages with a reverse slope entrance are a particularly striking example. It's "a basin within a basin!", which makes the risk of flooding extremely high.

Why aren't the owners being informed directly?

Despite the risk, many residents are not proactively warned by the authorities. Information on the topography of the land and depression areas is publicly available via an interactive map from the City of Montreal. However, it is considered the owner's responsibility to conduct their own research, especially at the time of purchase. Although the information exists, it is not always easy to interpret, leaving thousands of vulnerable people unaware of the risks.

How can you tell if you are in a risk area?

To determine if your property is located in a basin area, you can use the resources of the City of Montreal. The map of vulnerabilities to climate hazards is available online and allows you to check the topography of your neighborhood.

In addition to the map, here are some other signs to watch out for:

Land slope: Observe whether the land around your house slopes towards your foundations or if your driveway slopes downwards.
Flood history: If your home or your neighbors' homes have previously experienced sewer backup or basement flooding, there is a good chance that you are in a flood-prone area.
Proximity to low points: Look around your property. If you are in an area with a lower elevation than the surrounding streets, you could be vulnerable.

Why is prevention your best protection?

If Tropical Storm Debby taught us anything, it's that nature doesn't compromise. Insurers paid out over $2.7 billion in compensation , and those who were making their second claim often lost their coverage. Faced with such a situation, the best solution isn't to wait for the next flood, but to prevent it.

At Lave Uni Montreal

We understand your stress. We also know that once the rain starts, our team will be overwhelmed. Response times will increase, and you'll be left to fend for yourself against the rising water. By acting now, you'll ensure your family's safety and protect one of your most valuable assets.

Our solutions for you

We offer solutions designed specifically for the unique challenges of Montreal's topography.

We can install:

Foundation drains for efficient and durable water drainage.
Window wells to prevent water from entering through your basement windows.
Vertical drains for targeted solutions where you need them most.

Boîte de drainage pour l'eau de pluie provenant des gouttières
Levelling of the paving stones; Let's correct the slopes of your paving stones to ensure perfect drainage.
Filling the joints with polymeric sand; Let's apply high-quality polymeric sand to the joints of your paving stones to prevent weeds and maintain the stability of your surface.
Installation of gutters and drains; we design and install custom solutions, such as gutters for parking lots and custom drains to eliminate standing water in your garden or yard.
Slope correction; Let's analyze and correct the negative slopes of your land and lawn to divert water away from your house's foundations.
Correction de la pente et installation boîte de drainage.