Montreal plans to address high water use and leakage with new water strategy


City of Montreal officials say they may be at the top of the list when it comes to which city wastes the most water in the world, but the development of a new water strategy aims to change that fact.

While residents of cities such as London and Paris use approximately 130 litres of water per day, a new report suggests Montrealers approach tripling that figure with an average use of 367 litres per person each day, significantly more than the Canadian average of 220 litres. 

The next worst water waste offender on the report’s list is San Francisco at 322 litres per person per day.

One of the biggest culprits for wasted water in Montreal is leaks, according to a new report leading into a citywide public consultation for a new water strategy that will take place until October 4. The city’s previous water strategy expired in 2020. 

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“In a context of resilience and adaptation to climate change, this consultation aims to highlight the various problems of drinking water, wastewater and rainwater in public resource management,” states a city notice about the consultations. “It represents a unique opportunity to hear you voice your needs and concerns, share your vision as well as your opinion on the priorities in relation to this valuable collective resource.”

The companion report for the consultations shows that 26% of the overall water produced in Montreal was lost to leaks in 2020.

In 2020, Montreal produced 552 million cubic metres of water. Residential consumption accounted for 67% of the water use, with the majority (35%) for shower and bath water. The industrial, commercial and institutional sectors accounted for 29% of water consumption, while 4% was for municipal use. 

The report shows that 26% of the overall water produced in Montreal was lost to leaks in 2020.

On the private side, connections to the distribution network, of which there are 245,000 in Montreal, are a major source of water leaks. A single leak on a connection can contribute to losses of up to 10,000 litres of drinking water per day. In addition, the report estimates that 20% of buildings in Montreal have at least one leak in their plumbing fixtures, resulting in a waste of more than 500 litres of water per day.

Despite municipal restrictions, lawn watering during summer months has almost single-handedly contributed to a 30% to 50% increase in water consumption between 2 a.m. to 6 a.m. 

In 2018, Montreal also banned the use of water-cooled air conditioners, which can consume as much as 10,000 litres of water per day. Some city councillors have suggested that the products are still commonplace among the city’s businesses.

Montreal spends approximately $100 million per year for the rehabilitation and reconstruction of its water supply network, or nearly 32.6 kilometres of network per year, states the report. 

Montreal is responsible for treating the majority of Quebec’s wastewater. The new report targets industrial discharges into the Montreal River and the island’s bodies of water. As of 2022, about 35% of the sampling points around the island reveal areas where the water is not fit for use. 

The quality of inland rivers and lakes has remained relatively stable over the past 20 years, but only 38% of them have water of satisfactory quality, states the report.

Reverse connections have continued to be a major source of water pollution. This problem exists, especially in certain sectors of Montreal, where there are separate pipes for wastewater and for rainwater. This makes it possible to redirect rainwater to the nearest watercourse without going through the treatment plant. There is a reverse connection when the wastewater is routed to the pipes provided for stormwater. Wastewater is then discharged into the environment without treatment, which has a negative impact on water quality.

To improve water quality, Montreal has implemented a program to address these cross-connections, requiring building owners to fix the problem and reduce the amount of pollution entering water. Since the screening program began in 2015, nearly 11,000 buildings have been inspected and 908 reverse connections have been identified. Of these, 508 connection corrections have yet to be made.


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