Calgary Water Breaks

Calgary’s water emergency is just the start
By Meg Sears | Opinion | June 21st 2024

Flooding in Regina neighbourhood following asbestos cement water main break. October 10, 2022. Photo Julian Branch

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Three recent events drew attention to something people rarely think about until it’s too late — the profound fragility and importance of safe, clean drinking water.

On June 5, national news reported a “catastrophic” major water main break that wreaked havoc in Calgary. Reports are that the 50-year-old pipe was made of steel and concrete — it was not an asbestos cement or “transite” pipe. Further inspections revealed smaller “hotspots” for repairs that might extend water restrictions through the Calgary Stampede.

The next day, 3,237 kilometres away on Parliament Hill, federal Green Party co-Leader Elizabeth May and Canadian NGO Prevent Cancer Now held a news conference to talk about water mains — in particular, asbestos cement water mains — and the hazards associated with swallowing asbestos released from these aging pipes.


As infrastructure ages, Canada is experiencing increasingly frequent water main breaks, costing local governments millions in emergency repairs. Municipalities and citizens are enduring sinkholes and water advisories.

What many Canadians are blissfully unaware of is that aging asbestos cement water pipes make up a large number of those water main breaks. For example, between 2010 and 2022, the Saskatchewan capital experienced 2,477 asbestos cement water main breaks. Regina residents are not notified of the type of pipe material involved in breaks.

Prevent Cancer Now helped to craft a Parliamentary petition calling on the federal government to take action. It was authorized by Elizabeth May. In response, we learned that the Government of Canada is carrying out a national inventory of asbestos cement water pipes, with results expected later this year.

Asbestos is neither monitored, nor regulated in Canadian water, although asbestos cement water pipes deliver water to millions of Canadians. Since 2023, Health Canada has been reassessing its 1989 decision not to regulate asbestos in water. Public participation planned for later this year is now “anticipated” in 2025.

Asbestos is a particularly wicked problem, as the water pipes are out of sight, out of mind, just like lead-containing pipes and fixtures. Water may leave the treatment plant with low levels of asbestos or lead, but the pollution occurs enroute.

What many Canadians are blissfully unaware of is that aging asbestos cement water pipes make up a large number of water main breaks, writes Meg Sears @PreventCancerNw #asbestos @CanadianWater @CAPE_ACME #cdnpoli
Following these two events, pollution from pipes was in the news as the Investigative Journalism Bureau reported ongoing lead contamination of drinking water in Ontario schools from old lead pipes and fixtures.

There is really a single solution to water pollution from pipes — remove the source of lead or asbestos. We must replace this decaying infrastructure, as it only worsens with age.

Few people question what type of pipes bring water to their taps, or possible contamination. Health Canada proposes guidelines that provinces adopt, and supplies of drinking water are supposed to comply. The Guidelines for Canadian Drinking Water include a value for lead — there is no guidance proposed by Health Canada for asbestos.

The United States has regulated asbestos in water since 1992. The American Cancer Society highlights swallowing asbestos and “water that flows through asbestos cement pipes” on the asbestos and cancer risk page of its website.

Beginning in the early 1970’s, the U.S. Environmental Protection Agency (EPA) launched a two decades-long study of asbestos in water. In 1991, just one year prior to regulation, the EPA Science Advisory Board stated that “given the positive signal seen in some epidemiologic studies, plus well-documented evidence for the association between asbestos fiber inhalation and lung cancer, it is hard for the Committee to feel comfortable in dismissing the possibility of an increased risk of gastrointestinal cancer in humans exposed to asbestos fibers from drinking water.” Since then, evidence has strengthened, and asbestos fibres have even been visualized in bile duct and other tumours.

Health Canada said that it took the U.S. EPA information into account when it decided this century not to propose a guideline, but there was no normal process, and no public review of the scientific assessment.

A major impediment to Canadian assessment is the lack of data. Science-based assessment is impossible without data — you can’t evaluate risk without measuring exposure. Canada has no validated method or certified laboratories to measure asbestos in water, so we have no surveillance and no reliable statistics on drinking water.

An inventory of water infrastructure should yield data on the pipes. Given the increasing numbers of asbestos cement water main breaks, pragmatic, precautionary approaches would include prioritization of:

· Planned replacement, using the least disruptive technologies;

· Establishment of methods and laboratory capacity to measure asbestos in water;

· Scientific capacity and surveillance; and

· Use of Canadian data in research. The Canadian Urban Environmental Health Research Consortium (CANUE) group has this experience and expertise.

The Calgary water main break garnered national attention. Reports are that the 50-year-old pipe was made of steel and concrete. We wonder how the impacts of this single break compare with the cumulative health risks and impacts of thousands of breaks, floods and emergency responses, associated with asbestos cement pipes.

Chances are this is the first you are hearing about the subject of the Parliament Hill news conference, the day after Calgary’s calamity began. As one step in renewing Canada’s aging water infrastructure, that needs to change.

As chair of Prevent Cancer Now, Meg Sears champions healthy, sustainable choices by individuals, and on behalf of the public by governments – choices based on rigorous science, via laws, policy and regulation.


Meg Sears
Chair of Prevent Cancer Now
@PreventCancerNw