Single-family zoning is a type of planning restriction applied to certain residential zones in the United States and Canada in order to restrict development to only allow single-family detached homes. It disallows townhomes, duplexes, and multifamily housing (apartments) from being built on any plot of land with this zoning designation.
It is a form of exclusionary zoning, and emerged as a way to keep minorities out of white neighborhoods. Single-family zoning both increases the cost of housing units and decreases the supply. In many United States cities, 75% of land zoned for residential uses is zoned single-family.
Around 2020 many cities across the United States have started looking at reforming their land-use regulations, particularly single-family zoning, in attempts to solve their housing shortages and reduce the racial inequities which arise from housing segregation. These upzoning efforts would not require that new housing types be built in a neighborhood, it merely allows for flexibility in options. For example, changing a single family zoning district to a multifamily residential zoning district would not mandate single family detached homes be converted, nor would it prohibit new single family homes, it would just allow owners of those single family detached homes to subdivide their property, or owners of empty lots to build something other than a single family home.
In the late 2010s and early 2020s, states including California and Oregon as well as cities like Minneapolis and Charlottesville, Virginia have signed bills, made proposals, or started investigations to effectively eliminate single-family zoning. This includes requiring cities to approve two units and under certain conditions up to four units on single-family lots for example.
History
According to multiple sources, single-family zoning originated in 1916 in the Elmwood neighborhood of Berkeley, California, as an effort to keep minorities, specifically a Black dancehall and Chinese laundries, out of white neighborhoods. Real estate developer Duncan McDuffie was one of the early proponents of single-family zoning in this neighborhood of Berkeley to prevent a dance hall owned by a Black resident from moving into houses he was trying to sell. He worried that families of color moving into the neighborhood would decrease the desirability of the neighborhood and decrease property values. By advocating for single-family zoning, McDuffie and other developers at the time were attempting to price out social groups whom they deemed to be less desirable for the neighborhood. This makes single-family zoning one of many exclusionary zoning policies intended to limit who was able to afford living in a certain neighborhood. The goal of limiting certain neighborhoods to only single-family homes meant that only families who could afford to buy an entire house could live in the neighborhood. There was not the option to subdivide housing so that families who could not afford to buy the whole property could live in smaller units.
After the US Supreme Court's 1917 decision in Buchanan v. Warley, which declared explicit race-based zoning statutes unconstitutional, the court in 1926 decided in Euclid v. Ambler that it was a legitimate use of the police power of cities to ban apartment buildings from certain neighborhoods, with Justice George Sutherland referring to an apartment complex as "a mere parasite" on a neighborhood. This enabled the spread of single-family zoning as a means to keep poor and minority people out of white neighborhoods. In many cases, homeowners and neighborhood associations adopted covenants to prevent homes in their neighborhood from being sold to buyers of color. Restrictive covenants were legal until a 1948 Supreme Court decision in Shelley v. Kraemer made them unenforceable, though they continued to be included on deeds until the 1968 Fair Housing Act deemed that illegal as well. "Single-family zoning became basically the only option to try to maintain both race and class segregation," - Jessica Trounstine (associate professor of political science at the University of California, Merced)