Different areas of the city have different service providers for electricity, natural gas and water. If you have purchased a home you will need to set up accounts for all services. If you are renting, some services may be included in your rent.
Residents of the East or West end contact Hydro One at 1-888-664-9376, note: this is a voice recognition system, say "moving" to get to the right menu.
If your house is heated with oil, you can find a home heating company in the Yellow Pages listed under "Oils-Fuel".