The city is blaming a series of broken water mains, including one on Bloor Street West near Dovercourt Road, on the extreme heat gripping Toronto.

The Bloor Street water main broke around 4 a.m. on Friday, city officials say. Water was cut off to some 20 businesses in the area and the road was closed during the repair work.

The ground shifts with this kind of heat. That's likely the cause of these breaks. - Bill Shae, Toronto Water

Toronto police say all eastbound lanes on Bloor Street West, from Dovercourt Road to Rusholme Road, have been reopened.

Bill Shae, a director of operations with Toronto Water, said a "vintage" cast iron water main from 1888 broke.

"They're very thick and generally last a very long time, but when they crack, they crack big time," he said.

Shae said water main breaks aren't uncommon at this time of the year.

"The ground shifts with this kind of heat. That's likely the cause of these breaks."

Lyne Kyle, spokesperson for Toronto Water, said the water shutoff in the area only affects buildings along Bloor Street West from Dovercourt to Rusholme, not properties north or south of Bloor.

Kyle said crews have to locate underground utilities before they can start digging to make repairs. It is not yet known what repairs will be required and how long they will take.

Meanwhile, another water main break in the Weston Road area caused a large sinkhole and led the TTC to divert three bus routes.