Homeowners are responsible for maintaining properly operating isolating shut-off valves (taps) on both sides of their water meters. This including turning them off and on (at least once each year) to ensure they are working properly. If this is not done, corrosion and other factors can cause them to get stuck and break off when you do need to turn them off. The taps are usually located in the basement of your home near your water meter.
The following excerpt is taken from Item 13.b. of the Water Services Bylaw #30 of 2006:
"At his own expense, every owner shall install and maintain a properly operating isolating valve on both sides of the meter, being the inlet or upstream side and the outlet or downstream side."