In land use, a setback is the minimum distance which a building or other structure must be set back from a street or road, a river or other stream, a shore or flood plain, or any other place which is deemed to need protection.
[1] Depending on the jurisdiction, other things like fences, landscaping, septic tanks, and various potential hazards or nuisances might be regulated and prohibited by setback lines.
Local governments create setbacks through ordinances, zoning restrictions, and Building Codes, usually for reasons of public policy such as safety, privacy, and environmental protection.
As automobile ownership became common, setbacks increased further because zoning laws required developers to leave large spaces between the house and street.
Recently, in some areas of the United States, setback requirements have been lowered so as to permit new homes and other structures to be closer to the street, one facet of the low impact development urban design movement.