Sewage leaks into Calgary’s Bow River; mayor says city’s water is still safe to drink

CALGARY — Calgary Mayor Jyoti Gondek is reassuring residents of the city that their water is safe to drink after announcing a sewage pipe underneath the Bow River had to be shut down due to a leak.

Gondek told a news conference on Saturday that there are three pipes underneath the river that supply the Bonnybrook Wastewater Treatment Plant, and that the other two pipes have been able to handle the additional flow.

She said Alberta Health Services confirms drinking water in Calgary remains safe to consume.

“They have also stated that based on available data, the risk to the public as a result of this event is extremely low,” Gondek said.

The city’s general manager of operational services told reporters that staff first noticed the Bonnybrook plant was receiving less wastewater than normal on March 19, and they began looking for possible causes like seasonal fluctuations.

Doug Morgan said that on Thursday, crews took river water samples from near the plant for testing, and after learning on Friday morning they contained elevated E. coli levels, staff did another visual inspection of the river and spotted the leak.

“There are three pipes in that location that carry untreated wastewater under the river and to the treatment plant. Our crews began investigation to determine which of these three pipes was the source of the leak,” Morgan said at the news conference.

“By 2:30, we had identified which pipe was the issue, closed the valve to that pipe and rerouted the wastewater to the two other functioning pipes so that service could continue normally.”

Morgan said drinking water for the city is drawn upstream of the leak, and that E. coli levels in the river water will continue to be monitored. Other users of the river water downstream from Calgary have been notified, he said.

Calgarians, as well as their pets, are advised to avoid contact with the Bow River downstream of the Ogden Bridge, he said.

Since March 19, Morgan said the amount of wastewater that was arriving at the Bonnybrook facility continued to drop daily. He said there’s no word yet on the cause of the leak, and the city is still compiling an estimate on how much sewage leaked into the river, which he said will be based on how much less wastewater the plant has been receiving.

Gondek noted one of the three pipes under the river was added in 2006 as a backup for the system, in the event of a surge or a failure of the other pipes.

The mayor expressed frustration during the news conference that she wasn’t notified of the issue until Friday evening.

“The flow of information was disappointing,” Gondek said.

She said she called for a briefing at 8 p.m. Friday after she left what she described as “an important community event.” She said she felt it was urgent to tell Calgarians what was happening, but that the briefing didn’t end until 9:30 p.m.

Given the late hour and the fact that critical information, such as whether the leak had been stopped, was unavailable she said she decided to hold a media briefing Saturday.

In June 2024 Calgary residents were directed to avoid taking showers or baths, while some were told to boil their water as the city grappled with a major water main break that staff called unprecedented. The restrictions lasted for much of the summer.

Gondek was forced to apologize for communication flubs in the first few days following that infrastructure failure.

A City of Calgary committee is set to receive the final report into the catastrophic water main break this coming June.

This report by The Canadian Press was first published March 29, 2025.

— By Rob Drinkwater in Edmonton

The Canadian Press