RoydadNaft –  Residents of Calgary, the largest city in Canada’s main oil-producing province of Alberta, face running out of water and need to urgently cut their use after a critical water main break, city officials said on Friday.

A key pipe that carries supplies water to 1.2 million people ruptured on Wednesday evening, flooding streets, playing fields and a section of the TransCanada highway, the country’s main east-west route, which remains closed.

“This critical water transmission line has severely impacted the supply in Calgary’s reservoirs and the ability to move water across the city,” city officials said in a statement.

“Calgary is currently using more water than it can produce. If Calgarians do not reduce our water use, we are at risk of running out.”

Downtown Calgary is home to the vast majority of Canada’s oil and gas companies.

Crews have not yet been able to reach the damaged section of pipe, known as a feeder main, to start repairs and determine what caused the break but are “hopeful” that will happen later on Friday, the statement said.

The community of Bowness is under a boil water advisory and businesses have been told to stop using water for all nonessential services.

Outdoor watering is banned and residents have been asked to delay using dishwashers and washing machines and limit shower times.

The 11-kilometre pipeline, known as a feeder main, was installed in 1975 and is one of the most important and largest water supply arteries in Calgary.

“You can literally drive a truck through the feeder main that is broken,” Calgary Mayor Jyoti Gondek told a news conference on Thursday. “It’s a pretty significant piece of infrastructure.”

Gondek said crews were working around the clock, and repairs should happen within a day or two of the break being reached.