Calgary's water supply still at risk as crews continue water main repairs

Repairs continued Monday on a water main break in northwest Calgary that is still threatening the city's water supply and has triggered outdoor water restrictions.

But it will still take days to fix the 50-year-old piece of infrastructure that supplies approximately 60 per cent of the city — and the risk of running out of water remains a real threat, according to Calgary Mayor Jyoti Gondek.

"It may be a situation where you turn on the tap and nothing comes out," she said Monday on CBC's Calgary Eyeopener.

"As you draw water down on the reservoirs that are in your community, if we can't get them filled up as quickly as you are using the water, you may run out of water."

Crews have yet to identify what went wrong last Wednesday that caused the main to fail, but maintenance work had been done earlier this year.

The pipe, installed in 1975, is at the halfway-point of its 100-year lifecycle. The work completed in April involved putting in new technology to identify any further repairs that would need to be done.

More maintenance work was already scheduled for the fall prior to the break.

"The good news out of all of this, because the maintenance is scheduled, we have the parts and the equipment to do the repair," Gondek said.

In a press conference on Sunday, Nancy Mackay, the city's water services director, said further assessment of the pipe's condition needs to be completed before they can provide Calgarians with an updated timeline. 

The Bearspaw south water main, which is 11 kilometres long and as wide as two metres in parts, suffered a break that left hundreds of homes and businesses in the city's northwest without water and forced the closure of several roads and intersections, including 16th Avenue — part of the Trans-Canada Highway — in both directions.

The Stage 4 water restrictions put in place following the break remain in effect and the city continues to maintain a mandatory outdoor watering ban. Officials are also asking Calgarians to limit their non-essential water use by taking these additional actions:

In an update on Monday morning, Gondek said the efforts to cut water usage are making a difference, but she stressed they need to continue.

She suggested flushing a toilet fewer times a day, limiting showers to three minutes and doing laundry and dishes only with full loads would made a difference.

An early estimate of the amount of water used on Sunday was 457 million litres of water. The available supply was around 620 million litres.