What Montreal's water restrictions reveal about our aging pipes

What Montreal's water restrictions reveal about our aging pipes — and our habits

Water advisory prompts questions about state of infrastructure in city

A stretch of road on the western edge of Montreal’s downtown is reduced to a single lane as crews work behind orange fencing, with construction equipment, trucks and a temporary work trailer lining the roadside.

The work on Atwater Avenue is part of an urgent repair to a major water main beneath the road — a project that has prompted Montreal to ask residents across much of the island to reduce their water consumption this summer.

The city says the pipe will need to be shut down for several weeks while repairs are carried out.

The closure comes as two other major water conduits elsewhere in the network are already out of service for rehabilitation work, increasing pressure on the system just as water demand typically peaks.

As a result, Montreal is asking residents and businesses to reduce water use by roughly seven per cent, warning that further restrictions, including a watering ban, could be considered if necessary.

For Susan Gaskin, a professor of civil engineering at McGill University whose work focuses on water systems, the need for emergency repairs is not particularly surprising.

“Montreal is an old city,” she said. “We have quite an old system for potable water supply.”

The Atwater system dates back to the mid-19th century, and Montreal’s drinking water network now stretches across thousands of kilometres of underground pipes. Maintaining such a vast system is a constant challenge, Gaskin said, particularly as infrastructure ages.

“Often maintenance is a little bit left [aside], and if you leave maintenance for a while, then the bill gets higher and higher,” she said.

Still, she says the city’s decision to intervene before a major failure occurs should be viewed as a positive sign.

“It’s much better to do an emergency repair than have a break,” Gaskin said.

Why are Montrealers being asked to use less water when they're surrounded by it?

Large water mains such as the one under Atwater Avenue act as key arteries in the city’s distribution system. Water is pumped from treatment plants to reservoirs before travelling through major conduits and progressively smaller pipes to homes and businesses.

Under the current repair period, if water demand becomes too high, pressure throughout the system can begin to drop.

City officials say conservation efforts are intended to avoid precisely that scenario.

The request comes as Montreal continues to consume significantly more water than the Canadian average.

According to the city, average residential consumption reached 304 litres per person per day in 2024. The Canadian average is roughly 220 litres.

“We use a lot of water in Montreal, compared to the Canadian average. But it’s the first time we ask the population to reduce the use of water,” Chantal Morissette, head of Montreal’s water services, said at last week’s announcement.

She said she couldn’t recall a similar advisory to the public in two decades with the city.

Part of the difference can be explained by leaks, both inside buildings and throughout the broader network.

The city says it found at least one water leak in roughly 20 per cent of homes visited.

Montreal has also long been plagued by crumbling water pipes within its network — so much so that research has shown trees benefit by drinking from them.

The city says it has slowly cut down on the problem over the past few decades, with 40 per cent of treated water lost to leaks in 2001 compared to 20 per cent in 2024, according to a city report.

Behaviour at the individual level also plays a role, Gaskin said. She pointed to lawn watering, swimming pools, automatic irrigation systems and other outdoor uses as major contributors during the summer months.

“We have this understanding that there’s a lot of water in the St. Lawrence River,” she said. “Nobody has any concept that there might be any limitation on the amount of water.”

Reducing consumption by seven per cent, however, should be achievable, she said.

“If citizens put just a little bit of thought into it, it should be very easy to save that much water.”

But how can there be concerns about water use when Montreal is surrounded by water and has seen frequent rainfall in recent weeks?

Mohammad Reza Alizadeh, an assistant professor at Michigan State University and adjunct professor at McGill University who studies climate extremes and water resources, says the issue is not a lack of water.

“It’s more about the timing and also the location of the water," he said in an interview.

Quebec has abundant freshwater resources, Alizadeh noted, but water demand can still place pressure on infrastructure systems during specific periods of the year.

Montreal to build $70M underground water basin near downtown to reduce flooding

Last week, Quebec Municipal Affairs Minister Samuel Poulin said the province is “ready for a discussion” about drinking water pricing and water metres, noting that municipalities using metres have seen significant reductions in consumption.

The City of Montreal imposed water metres on the commercial, industrial and institutional sector, which led to a reduction in water usage. But city spokesperson Hugo Beaudoin said there were no immediate plans to put them in place for residential buildings.

Bourgoin said such a system is “demanding in terms of financial and operational resources" and “must therefore be considered carefully.”

Aatefeh Padidar is a journalist with CBC News based in Montreal. You can reach her at aatefeh.padidar@cbc.ca

With files from Ainslie MacLellan