Setbacks for any portion attached to the main dwelling are determined by the zoning classification that the property is located. If you do not know what zoning the property is, the zoning map will be helpful.
Once you have determined your zoning you can review the Schedule of Regulations chart here you can find information regarding minimum lot width and area, maximum lot coverage, maximum building height, property line setbacks, and minimum floor area per dwelling.
Setbacks for accessory structures are that are detached, must be a minimum of 10’ from any building, cannot be built less than 5’ from the side or rear property lines, and can not be nearer to the front property line than the face of the house. (Corner lots have two front property lines)