Calgary working to repair major water main break

Key Takeaways:

• Calgary remains under Stage 4 water restrictions after a major Bearspaw South Feeder Main break, with treated-water storage around 496 million litres — below the roughly 600 million litres the city says is needed to stabilize the system — and officials urging immediate indoor conservation to restore system balance.
• Repairs are advancing along 16th Avenue N.W. as crews pump out pooled water, fully expose the damaged pipe and begin internal camera inspection, while the city installs temporary distribution bypasses and reassesses how it manages known deterioration on the feeder main.
• A boil-water advisory remains in place for parts of Parkdale, Montgomery, Point McKay and West Hillhurst, and the city is warning residents in the impacted area to boil tap water for one minute before consumption or food preparation while it continues daily updates.

The Whole Story:

The City of Calgary says it is still working to repair a major water main break in the Bowness and Montgomery area, with the city remaining under Stage 4 water restrictions and some northwest neighbourhoods still under a boil-water advisory.

In an update Thursday, the city said treated-water storage was sitting at about 496 million litres — below the roughly 600 million litres it says is needed to stabilize the system. The city said the system saw a net loss of about 100 million litres over the previous 24 hours, putting Calgary in what it calls the “Red Zone,” with treatment plants operating at full capacity and no redundancy.

Calgary Emergency Management Agency chief Susan Henry urged residents to immediately reduce indoor water use, including limiting showers to three minutes, flushing toilets only when necessary and running dishwashers and laundry only when full.

A boil-water advisory remains in effect for parts of Montgomery, Parkdale, Point McKay and West Hillhurst, with residents advised to bring tap water to a rolling boil for one full minute before using it for drinking, brushing teeth, preparing food or making infant formula, among other uses.

The city says the break happened around 8 p.m. Tuesday on 16th Avenue N.W., east of Sarcee Trail, and that its emergency operations centre has been activated. It also says 16th Avenue N.W. at Sarcee Trail remains closed in both directions, and motorists are being asked to avoid the area.

On the repair site, the city said crews pumped out water around the break overnight to allow work to proceed safely, and that the damaged pipe section is now fully exposed. The city said a camera inspection inside the pipe is underway to help determine the extent and cause of the failure.

Michael Thompson, the city’s general manager of infrastructure services, said the Bearspaw South Feeder Main has been operating with known areas of deterioration, and that the latest failure is prompting a reassessment of how the city manages risk on the line.

The city said it completed 23 urgent pipe repairs following inspections in 2024 and installed a real-time acoustic fibre-optic monitoring system to detect wire breaks, adding that the monitoring system was functioning normally at the time of the Dec. 30 break.

The latest break comes after what the city has previously described as a catastrophic failure on the Bearspaw South Feeder Main on June 5, 2024 — a major line the city says distributes a significant share of Calgary’s treated water.

The city says that break was repaired later in June 2024, along with five additional priority locations identified during the response. It says it carried out additional repair work on 21 feeder-main segments in August and September 2024, followed by further repairs in October and into late November 2024.

The city says it has repaired 29 pipe segments since June 2024, installed fibre-optic acoustic monitoring and implemented interim measures to help improve distribution while advancing longer-term work intended to add redundancy and strengthen system reliability.

In its final forensic investigation into the 2024 break, the city said consultants found multiple contributing factors — including microcracking or prior damage in the pipe’s outer mortar layer that allowed conditions for prestress wire deterioration, chloride penetration in some pipe sections, severe pitting and corrosion with brittle wire breaks, and evidence of hydrogen embrittlement and stress-corrosion cracking, along with soil conditions showing elevated chlorides in some areas.