Vandals opened 66 fire hydrants between late Saturday night and early Sunday morning, and another 60 between Sunday night and Monday morning, causing some street flooding and a lot of inconvenience.
Crews from Epcor were called out to cap the hydrants, and estimated the water loss at $77,000.
"There was some street flooding. Thankfully there doesn't appear to be any damage to the hydrants, but certainly it is an inconvenience and a cost when you have one of your crews out overnight turning off fire hydrants," Epcor spokesman Doug Downs said.
Several neighbourhoods suffered low water pressure, and there have been reports of flooded basements and damage to driveways.
Police are investigating.
This is the second time in a month that vandals have opened up fire hydrants in and around the city.