As daily water use in Calgary remains above target during repairs to a major feeder main, a city official warns the effect on pumps and other infrastructure is like a car's engine running too hard for too long.

Calgary's director of climate and environment, Carolyn Bowen, said in a video update on the city's water situation Sunday that when water use is above the 485-million-litre-per-day target, preventative maintenance becomes challenging.

The city used 496 million litres of water on Saturday, and was above 500 million litres in the days before that. The city says it's on track to complete repairs on the water main by September 23rd, but in the meantime, Calgarians are banned from using potable water outside, and are being asked to skip toilet flushes and hold off on laundry and dishes.

Bowen says over the past few days, there was a pump failure and a malfunctioning component'' in the water-treatment process, which she says highlights the risk of running the system above the target.

She says when water demand exceeds 500 million litres, maintenance switches from preventative to reactive.