When zoning laws began to proliferate in the 1920s, they were a newly imposed restriction on what homeowners could do with their properties. In those days, most people lived in long-established communities in cities. Today, after 70 years of suburbanization following World War II, the large majority of homeowners bought their homes in suburbs built in response to market demand for single-family living. Local governments (typically county governments outside the main city) responded to the kind of housing the developers wanted to create to meet the growing single-family market demand.
In effect, postwar single-family zoning represented an agreement under which homebuyers accepted restrictions on other types of uses in their neighborhood in order to be protected from negative externalities that neighbors might create, without the protection of the covenant provided by single-family zoning.
