Preventing flooding in rental properties: best practices for landlords

With the increasing frequency of heavy rainfall in Quebec, particularly in Montreal, it is essential for rental property owners to implement concrete measures to reduce the risk of flooding. Here is a set of best practices to adopt.

1. Preparation and infrastructure maintenance

Regular cleaning of drains and gutters should be done at least twice a year, in spring and fall, as well as after heavy rains. This includes gutters, downspouts, roof drains, catch basins, and window wells. Cleaning prevents debris buildup that can block drainage and cause backups or overflows.
Foundation inspection is also essential. Look for cracks or signs of water infiltration, apply waterproofing products as needed, or contact a specialized contractor.
It is recommended to check the drainage system around the building. Ensure the ground slopes away from the foundation. Installing or upgrading French drains may also be necessary, especially in high-risk areas.

Inspecting the integrity of exterior cladding is another key step. Look for cracks or deterioration in masonry, wood, or aluminum siding. A damaged exterior envelope can promote water infiltration.
Lastly, check the waterproofing of skylights (if any). Inspect the caulking and glass condition, especially on older units, to prevent roof leaks.

 

2. Pumping systems and backwater valves

Installing a backwater valve on the main sewer line is often required by municipalities. This device prevents sewage from backing up into units when the system overflows.

It is also advisable to install or maintain a sump pump. A backup pump with a battery is recommended in case of power failure. It is important to test the system before each rainy season.

 

3. More advanced prevention measures

Waterproofing foundations involves adding membranes or exterior barriers, combined with efficient perimeter drainage.

Raising building openings such as storm drains, basement windows, or access hatches can provide better protection. Installing flood barriers, whether temporary or permanent, is also a good practice.
Implementing stormwater management systems, such as green roofs or rain barrels, helps reduce pressure on municipal sewer systems. These systems also allow water to be reused for non-potable purposes.

Particular attention should be paid to water accumulation on flat roofs, especially when drains are clogged. Unclogging a roof drain without precautions can create pressure in the plumbing system, causing backflows through other drains such as basement toilets or showers.

The safest method is to first pump out accumulated water using a submersible pump and garden hose, directing the water away from the foundation to a suitable location. Once most of the water is removed, it is safer to clear the clogged drain.

In any case, if the volume of water is too large, if the drain cannot be easily cleared, if the roof structure appears weakened, or if weather conditions are dangerous, it is strongly recommended to call a professional.

 

4. Tenant communication and education

To support this approach, CORPIQ provides its members with a ready-to-use letter template. This document helps effectively raise tenant awareness about appropriate behaviors in the event of heavy rain or flooding and encourages proactive communication between landlords and tenants.

It is also recommended to prepare an emergency plan. This should include contact information for flood situations, locations of shut-off valves for water and electricity, and a list of emergency contacts (plumber, contractor, insurance).

 

5. Regulatory and insurance considerations

Landlords must stay informed about the City of Montreal’s requirements. Some subsidies may be available for installing backwater valves or upgrading drainage systems.
Finally, it is essential to verify that your insurance coverage is adequate. Make sure your policy covers sewer backups or water infiltration, and review it annually with your broker.

 

By implementing these measures, landlords not only protect their buildings but also help strengthen the resilience of the rental housing stock against the increasing impacts of climate change. Before modifying your landscaping, consult an expert to avoid worsening flood risks due to poor water drainage. A well-planned preventive approach can make all the difference when a storm hits.

To consult our fact sheet that summarizes our tips for preventing floods, click here.