In Practice
The rear setback determines the buildable limit of your lot from the back property line. The space between the primary dwelling and the rear property line is where detached garages, sheds, and accessory dwelling units are commonly constructed, though those structures carry their own setback rules that may be more permissive than the rear setback governing the primary structure. Confirm both the primary dwelling and accessory structure rear setback requirements for your zone before planning any rear-yard development.