If you come across potholes or road maintenance issues you can call 311 Toronto or you can use their online form to submit a request for repair.
One of the I Bike TO bloggers has used this service a few times to report such problems as big construction trenches that have been left open for bicycles to fall into. It helps for us to all be vigilant and get the city to fix up the roads! The municipal government has a legal duty of care to keep roads in working order for all road users.