Water

Where the breaks fall matters more than how many of them there are.

Metro Vancouver commissioned the engineering firm WSP Canada to assess the seismic vulnerability of the regional water supply system. [2] [1] The study was published inside Metro Vancouver in February 2022. It reached the public two months later, when a heavily redacted copy released under freedom-of-information law was obtained by Glacier Media, which reported it in April 2022. Everything in this section comes through that reporting. [1]

Under a magnitude 9.0 megathrust, the offshore earthquake where one tectonic plate slips under another along hundreds of kilometres at once, the study modelled:

• 267 water main failures across the region and its 21 municipalities.
• 22 water mains rated at high seismic vulnerability, running through the North Shore, Vancouver, Burnaby, New Westminster, the Tri-Cities, Maple Ridge, Richmond, Delta and Surrey.
• About 60 breaks across the 71 water crossings, including three to four in the hardest category, which is the Fraser River, the Pitt River, False Creek and Burrard Inlet.

[1]

The 267 counts failures anywhere in the network, across the whole region. The 60 counts breaks at the 71 river and inlet crossings alone, the part of that total falling on the assets hardest to reach.

The figures come from a review of 123 existing reports on reservoirs, pump stations and pipelines. They do not come from a single model run. [1] They are more than eight and a half times the failures projected by the region’s previous study in 1993. [1] The study is four years old.

About two thirds of the roughly 300-page report is blacked out in the public version. Two of the withheld pieces are what a restoration estimate would be built from: the number of leaks and breaks per main, and the damage estimates for 21 water storage facilities. Both were removed under freedom-of-information exemptions. [1]

Metro Vancouver’s own Drinking Water Management Plan 2026, which is the region’s governing drinking water document, contains no restoration estimate of any kind. It names seismic risk as a core pressure, and the first action under its resilience strategy is to “increase the seismic resilience of the water system by conducting prioritized structural analysis to identify seismic vulnerabilities”. [3]

In 2026, identifying the weak points is still work to be done.

Metro Vancouver owns the transmission mains; the member municipalities own the pipes in the street. The plan’s third action commits to coordinating with those municipalities “to identify points of possible failure”, which says in the region’s own words that the joined-up picture across that seam has not been assembled yet. [3]

“Disruption to water and wastewater systems are expected for many months following the event.” [5] The sentence is qualitative, it covers sewers in the same breath as water, and it is region-wide. It makes no claim about a specific pipe. The province wrote it for its shallow crustal M7 planning scenario.

The province’s Cascadia assessment states that “people are thirsty within 24 hours”, and that “distributing bulk potable water across the affected region remains challenging for the first four to five days”. [6]

The four to five days are about trucking water to people; the many months is about repairing the network. Merging them would suggest water comes back in a week.

New Westminster’s potable water emergency response plan carries a damage and duration table in its earthquake annex: 200 to 300 breaks in a 475-year event, at “approximately 1-3 days per break”. It gives “weeks to months” for the loss of the regional supply through landslides. [7]

It covers New Westminster’s own distribution pipes and nobody else’s. Its scenarios are 1-in-100 and 1-in-475 year events, far below the level either scenario described here is built on, so the break counts do not transfer to them. The one to three days is how long a single break takes to repair, not how long the city waits: turning it into a restoration time needs a crew count the plan does not give. The weeks to months attaches to the regional supply being cut by landslides, not to those 200 to 300 breaks. And the table is a response plan’s planning assumption. No study produced it.

Metro Vancouver has published nothing comparable.

Metro Vancouver is replacing its river and inlet crossings with deep bored tunnels “designed to ensure delivery of drinking water in the event of a major earthquake”. It says there are five, and its construction listing names four of them. [8]

The Port Mann water supply tunnel, completed in 2017, was the first deep crossing of this kind in the region. [12]

Metro Vancouver describes the new tunnels the same way each time, as meeting current seismic standards and as built so that water keeps flowing after a major earthquake. Those crossings are where about 60 of the 267 failures fall, and they are the repairs that take longest.

Elsewhere the work runs later. The seismic phase of the Palisade Lake outlet works is scheduled to start in the mid-2030s and finish in the early 2040s, timed so that draining the lake does not hit summer supply. [13] As of 2023, four reservoirs built before the 1990s still needed upgrading. [14]