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Water management to cost Montreal billions as city seeks public's input


Aging infrastructure, climate change and population growth are putting Montreal's water resources under considerable pressure.

Faced with the magnitude of the issues at stake and the investments planned, the city is launching a public consultation on the future of water on its territory.

Montreal wastes too much drinking water, and discharges too many pollutants into the St. Lawrence River, its aging infrastructure is unable to cope with the ever-increasing quantities of water discharged during torrential rains, and the city does not have enough money to update and adapt its water management infrastructure.

These are just some of the findings of a report prepared by the Commission sur l'eau, l'environnement, le développement durable et les grands parcs.

Canada is among the countries that waste the most drinking water, and the City of Montreal is one of the worst in the country in this regard, according to the commission's report.

The residential water consumption of Montreal's population stands at 367 litres per person per day, according to 2020 data, compared with the Canadian average of 220 litres.

"In Paris, it's 120 litres per day, and in London, 140 litres," explains Maja Vodanovic, responsible for consultation with the boroughs and water on the City of Montreal executive committee.

Water leaks in the distribution network are partly responsible for this poor record. The municipal administration estimates that a quarter of all wasted water comes from leaks.

"There are leaks in the public network, but there are also a lot of leaks in homes," Vodanovic told The Canadian Press, adding that "there are still a lot of businesses that use drinking water for air conditioning."

Maja Vodanovic invites the population to participate in the public consultation to find solutions to these problems.


According to the commission, industrial discharges into the island's river and water bodies are constantly increasing, and only 38 per cent of waterways have "satisfactory quality."

"We now know that the St. Lawrence River is one of the most polluted rivers in terms of microplastics. It is in the same category as the highly polluted rivers of Asia", said Vodanovic, referring in particular to per- and polyfluoroalkylated substances (PFAS), which are found in many consumer products and can cause health problems.

A woman looks out at the St. Lawrence River on Friday, June 30, 2023 in LaSalle, Que. THE CANADIAN PRESS/Christinne Muschi

According to the elected representative, we need to act at source to reduce these types of pollutants in the water, particularly when clothes are washed in washing machines that don't contain the appropriate filter.

Reverse connections of buildings -- where sanitary and storm sewers cross -- are also a major source of pollution. When flooding occurs in areas where buildings have reverse connections, sanitary wastewater flows into the Rivière des Prairies and the St. Lawrence River. The wastewater is thus discharged untreated into the environment.


According to the person in charge of consultation with the boroughs and water on the executive committee, the City of Montreal has received 20,000 reports of flooded residences since 2013, and "this number will increase."

Even if we redid all the sewers, which would cost between $7 and $8 billion, there would still be flooding.

She pointed out that adapting to climate change also involves "modifying the built environment of some houses, by putting in low walls, flap gates, drains," adding that the city needs to "make concrete basins" and "change the geometry of certain streets so that water is channelled into vacant lots."

Adapting to climate change also requires green infrastructure. More vegetation is needed to absorb rainwater to prevent it from overloading the city's aging underground network infrastructure.

This includes the use of green roofs, rain gardens, water retention basins and permeable surfaces to capture and store water.

"According to projections for 2050, critical rainfall intensities will increase by an average of 15 per cent compared with today, and the frequency of flooding is likely to double," according to the report by the Commission sur l'eau, l'environnement, le développement durable et les grands parcs.

Vodanovic estimates that $1 billion per year is needed to finance water management.

"This is one of the reasons why all cities are asking the Quebec government to set up a Green Pact of $2 billion per year for the next five years," Vodanovic, also the mayor of the borough of Lachine.

The public consultation on water management will run until Oct. 4, and the recommendations will be presented and adopted at a public meeting on Dec. 5.

This report by The Canadian Press was first published in French on Aug. 14, 2023. Top Stories

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