Following the torrential rainfall of June 20, 2026, several residents submitted questions to the City regarding the weather event, stormwater management, municipal infrastructure, and measures that can be taken to better protect their properties.
As indicated in the news release of july 29, the current context limits the information the City can communicate on certain matters. This Frequently Asked Questions (FAQ) page was therefore developed taking into account the main questions and concerns raised by residents and brings together the information that can currently be shared, as well as useful resources.
The FAQ will be updated as needed, as new information becomes available for public release.
On June 20, 2026, a period of very heavy rainfall affected Montreal’s West Island. The storm system moved slowly, resulting in significant rainfall accumulations over a very short period in certain areas.
In Dollard-des-Ormeaux, the data collected indicate that 100 to 170 mm of rain fell in about one hour in certain parts of the municipality. The intensity of the precipitation – that is, a very large amount of water falling in a very short period of time – is a key characteristic of this event.
During a storm, the amount and intensity of rainfall can vary considerably from one area to another. On June 20, the storm cell reportedly remained almost stationary over the area for an extended period, releasing large amounts of water over a relatively limited area.
Centennial Lake is an important stormwater retention infrastructure for the City. During the June 20 event, its water level rose by just over 2 metres (twice its usual level) in a very short period of time, highlighting the significant amount of water that fell in the area during the storm.
The volume and intensity of rainfall recorded on June 20 were beyond the conditions Centennial Lake is intended to manage.
Yes. The City has conducted a risk analysis focusing particularly on heavy rainfall and heat, to better understand the territory’s vulnerabilities and guide the planning of adaptation measures. This assessment was submitted to the Government of Quebec on December 19, 2025, as part of the OASIS program.
Yes. The City implements an annual intervention plan for the inspection, cleaning, maintenance and rehabilitation of its sanitary and storm sewer networks.
Each year, over 7,000 metres of the network are inspected using specialized cameras. These inspections help assess the condition of the pipes, identify priority areas for intervention and plan rehabilitation work. The network is also subject to a regular cleaning and maintenance program.
Following the significant rainfall in August 2024, several initiatives were already underway.
In particular, the City had authorized the construction of an underground retention basin at Terry-Fox Park in August 2025; construction was completed in November of the same year. By fall 2025, the basin was already fully operational.
The construction of a second underground retention basin in the Tecumseh–Frontenac area was also included in the Triennial Capital Works Program adopted by the City Council in December 2025, and construction began in June 2026.
At the same time, the City had secured nearly $1 million through the OASIS program to conduct risk assessments, identify priority areas and develop green infrastructure solutions. Building on the analyses completed through the program, five green infrastructure projects were approved by City Council. The City has submitted applications for funding to support their implementation and is currently awaiting responses, while continuing to explore additional funding opportunities.
Retention basins are used to temporarily hold back some of the stormwater during heavy rainfall and slow its flow into the municipal sewer network.
The underground basins at Terry-Fox Park and in the Tecumseh–Frontenac area are among the measures implemented by the City to increase stormwater retention capacity across the territory.
Yes. As part of the initiative funded through the OASIS program, the City conducted a risk analysis focusing on heavy precipitation and heat waves. This data was incorporated into analyses aimed at better understanding risks across the territory and supporting the planning of adaptation measures.
Yes. Depending on their circumstances, homeowners may be eligible for various financial assistance programs offered by the Government of Quebec.
Financial assistance following a disaster
The Government of Quebec offers a General Financial Assistance Program Regarding Disasters for certain events recognized as eligible. The program is intended, among other things, to support homeowners and tenants whose damages are not covered by their insurance or whose coverage is insufficient, subject to the conditions of the program. It does not replace home insurance; residents should first contact their insurer.
→ Consult the General Financial Assistance Program Regarding Disasters
Financial assistance to better protect your home
As of October 1, 2026, the Government of Quebec will also introduce the new Rénoclimat – Adaptation component, which will provide financial assistance for certain work intended to improve the resilience of homes to flood risks.
The measures announced include the installation of check valves, battery-powered sump pumps and the purchase of removable flood barriers. The Government of Quebec has announced direct assistance ranging from $700 to $1,000 for certain simple measures and assistance of up to $35,000 for certain more complex work, subject to the applicable eligibility requirements.
Homeowners are encouraged to consult the Government of Quebec directly to find out which work is eligible, the amounts available and the applicable conditions when undertaking their application process.
→ Consult Rénoclimat – Adaptation
* The information presented above is provided for informational purposes only and is based on information published by the Government of Quebec. The City of Dollard-des-Ormeaux does not administer these programs, determine eligibility criteria or have any influence over their management or allocation.
Every property has its own characteristics. It is therefore recommended that you consult qualified professionals to assess your home’s specific situation and determine which protective measures may be appropriate.
To assist homeowners in this process, several resources outline measures to improve a home’s resilience against water infiltration and flooding.
In particular, the City published a brochure on water infiltration prevention in 2025, presenting various measures that can help better protect a property.
→ Consult the City’s water infiltration prevention brochure
Homeowners can also consult Cohabiter avec l’eau, which offers information and tools to better understand possible adaptation measures for their homes.
For more than 10 years, the City’s regulations have included stormwater management requirements for redevelopment projects.
When an existing property is redeveloped, stormwater must be retained on-site, and its discharge into the municipal storm sewer system must comply with the maximum flow rate permitted by the City. These requirements, which did not previously exist, mean that a redeveloped property discharges less stormwater into the municipal system after redevelopment than it did before the work.
In addition, many redevelopment projects take place on properties that are already highly impervious. Requirements applicable to new construction also include de-paving measures to reduce impervious surfaces.
Do you have a question or comment?
You can submit your question or comment using the form below. The questions received will help the City identify recurring concerns and update this FAQ, where possible.
