A Montreal law firm specializing in class actions has filed two separate applications with the Quebec Superior Court in connection with the June 20 flooding in the Greater Montreal area.

Lawyer Jeff Orenstein of Consumer Law Group filed two applications seeking authorization to launch class actions against the borough of Pierrefonds-Roxboro in Montreal and the neighbouring municipality of Dollard-des-Ormeaux. The applications are available on the law firm’s website, which also allows affected residents to join the class action.

In an interview with Jeremy Zafran of the English-language weekly The Suburban, published on July 5, Orenstein said that 815 people had joined one or the other of the class actions filed by the firm. He suggests that affected residents wishing to join the class action submit a notice of claim to the municipality concerned within the 15-day period required under municipal regulations.

He estimates that between 1,000 and 1,500 properties were flooded during the torrential rainfall of June 20, 2026. According to Environment and Climate Change Canada, the rainfall was caused by several stationary thunderstorms that dropped between 100 and 170 millimetres (mm) of rain, depending on the area. The vast majority of the precipitation fell during a four-hour period on that Saturday afternoon.

Most insurance policies include an endorsement covering water damage, although they may contain sub-limits or exclusions. Before a municipality or the Quebec government pays any compensation to affected residents, they must first contact their home insurer to verify their coverage.

Damage to homes can also result from above-ground water entering through roofs, walls, doors and windows, according to the Insurance Bureau of Canada (IBC). The IBC advises affected residents to keep invoices and receipts for all expenses incurred in cleaning up the property, and to take photographs of the damage and of any belongings that cannot be salvaged and must be discarded.

The public disaster insurance scheme also imposes conditions on eligible damages. Quebec’s General Financial Assistance Program Regarding Disasters covers watercourse overflows occurring during spring freshets or caused by torrential rains. Damage resulting from sewer backup associated with the overflowing of a watercourse is covered by the program. If the sewer backup is caused solely by torrential rain, the damage is not eligible under the program.

An exceptional event

At Insurance Portal’s request, the IBC confirmed that the event will be included among the catastrophic losses tracked by Catastrophe Indices and Quantification (CatIQ). The insured damage threshold required for an event to qualify as a catastrophe is $30 million.

The June 20 event also prompted the Autorité des marchés financiers, on June 23, 2026, to relax the rules governing the use of temporary claims staff by claims adjusting firms in order to help them manage the high volume of claims.

Affected firms will be permitted to use uncertified individuals until December 22, 2026. During that period, those employees will be authorized to handle claims by telephone with a value of up to $30,000, instead of the $7,500 maximum set out in the legislation.

In its July 9 newsletter, the Chambre de l’assurance also encouraged its certified members to consult the section of its website outlining their obligations in such situations and their supervisory responsibilities regarding the activities of uncertified individuals.

Similar allegations

In the application against the borough, the proceeding was filed on behalf of I. Beaudry and seeks to represent all affected residents in the area who suffered damage related to the June 20, 2026 rainfall flooding. In Dollard-des-Ormeaux, the representative identified in the application is R. Wolofsky.

The allegations made against the Montreal borough are identical to those directed at the neighbouring municipality:

  • failing to take adequate precautionary measures before the storm for further storage of rain water, such as draining stormwater retention ponds;
  • failing to take proper action to address the risk of flooding by installing adequate systems that absorb, detain and slowly release rainwater, such as sponge parks, catch basins and retention facilities (cisterns and reservoirs);
  • failing to adequately mitigate the flooding at the time of the incident, such as water diversion, water pumping, clearing drainage blockages, using movable barriers or using secondary catchment zones;
  • failing to upgrade and/or maintain their aging sewer or drainage systems.

According to the applicants in both class actions, the defendants—the borough of Pierrefonds-Roxboro, the municipality of Dollard-des-Ormeaux and the City of Montreal—should have known that storm sewer overflows were likely once rainfall exceeded 100 mm.

The August 2024 precedent

The Greater Montreal area experienced a similar situation on August 9, 2024, during the passage of Tropical Storm Debby. That event generated approximately 25,000 claims and more than $2.5 billion in indemnity payments, making Debby the costliest insured loss in Quebec’s history, surpassing the January 1998 ice storm.

This part of the island’s west end “is highly vulnerable to climate risks because its naturally low-lying topography encourages the accumulation of surface water during heavy rainfall.” Streets “were transformed into rivers,” and many homes were inundated by several feet of contaminated water, according to both applications.

The representative plaintiff in the Pierrefonds-Roxboro case had a backwater valve installed in the basement of the home in 2022. Despite this, approximately 15 cm of water flooded and damaged the basement on August 9, 2024. In May 2026, a plumber installed a second main backwater valve for the entire house. Despite this, on June 20, 2026, 30 cm of contaminated water flooded the basement and ruined the repairs completed in 2025.

The situation experienced by the applicant in Dollard-des-Ormeaux is similar. Despite the installation of a backwater valve in 2017, the home’s basement was flooded to a similar extent on August 9, 2024, and again on June 20, 2026. There as well, the damage caused by the recent rainfall affected recently completed renovations.

Intact Financial Corporation published its estimate of catastrophic losses for the second quarter of 2026 on July 8. Across Canada, the insurer estimated the impact on its operations at $295 million, notably due to “heavy rainfall that resulted in flooding and water and wind damage across several regions.”

Contacted by Insurance Portal, Intact spokesperson Caroline Audet stated that the company does not disclose the number of claims associated with a specific event. However, she noted that one-third of the files related to the June 20 event in Montreal had been closed as of July 9, 2026.