Am I required to pay an employee in ontario to be on call even if they don't come into work or get a call? They need to be available in the even their is a call but they don't necessarily take calls everyday.

Depending on the nature of the employees work, you may be required to pay that employee for time spent "on call". I strongly recommend that you schedule a consultation with one of our lawyers to go over your situation in more detail to provide you with a more substantive analysis.