After a major feeder water main break plunged Calgary’s water supply into a critical state, city officials are now asking Calgarians to use 25 per cent less than they did yesterday, sounding the alarm that the city is at risk of running out.

The Bearspaw south water main — which is 11 kilometres long and as wide as two metres in parts — suffered a break Wednesday night that left hundreds of homes and businesses in the city’s northwest without water.

Just before 7 p.m. Wednesday, the break caused streets to suddenly flood in the Montgomery area around Home Road, forcing the closure of several roads and intersections, including 16th Avenue in both directions.