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. During the 20th century, many advanced European and North American cities introduced restrictions on dense forms of housing, subsidizing single-family housing. In many United States cities, 75% of land zoned for residential uses is zoned single-family. Amid worsening housing crises in many cities, YIMBY movements and urbanists have become increasingly potent political forces, pushing for upzoning of areas exclusively preserved for single-family housing.
Beginning in the late 2010's, 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.
From the late 2010's and into the 2020's, multiple 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)
Sonia Hirt, professor of landscape architecture and urban planning at the University of Georgia, states that "In the early 1900s, the racially and ethnically charged private restrictions of the late nineteenth century were temporarily overshadowed by the rise of municipal zoning ordinances with the same explicit intent." Hirt says single-family zoning is a uniquely American phenomenon: "I could find no evidence in other countries that this particular form — the detached single-family home — is routinely, as in the United States, considered to be so incompatible with all other types of urbanization as to warrant a legally defined district all its own, a district where all other major land uses and building types are outlawed."
Statistics
In many United States cities, 75% of land zoned for residential uses is zoned single-family, and across the state of California as a whole, that number is greater than 66%. 94% San Jose, California 89% Arlington, Texas 84% Charlotte, N.C. 81% Seattle 79% Chicago 77% Portland, Oregon 75% Los Angeles 36% Washington, D.C. 15% New York City
Effects
Property values Because this type of zoning reduces the amount of land available for new housing, it pushes development into poor, minority communities or to land beyond the borders of the city. Local public employees like teachers, firefighters, and police officers are often priced out of feasibly living in the communities they serve—even in municipalities that require these workers to do so. These cases are the most consistent exception to these policies that are "acceptable" to affluent residents. Housing developments in these areas designed to be affordable are frequently only granted an exception to zoning rules on the condition that they gave priority to those either living or working there. Even then, local concerns over affordability for existing town residents and public employees often fails to effect changes in zoning laws or the approval of new, denser, more-affordable developments due to local resistance. However, evidence suggests that larger, more heterogenous suburbs are more responsive to calls for change, likely due to an already-existing local population harmed by these policies.
According to Andrew Whittemore, a professor of city and regional planning at the University of North Carolina-Chapel Hill, one effect stems from the belief that higher density housing in neighborhoods decreases housing values, and that one role of the government is to keep homeowner's house values high, and because cities have prioritized single-family homeowners above other groups, this has turned city planners into wealth managers when city planners should be concerned with using zoning to prevent harm. Sonia Hirt supports this, stating, "In the United States, private profit as a result of zoning ordinances that preserved and enhanced 'investment values' was not only fully expected, it was a major zoning goal."
This effect is furthered by the unique reliance of Americans on homeownership and the value of such properties in securing a long-term, stable quality of life according to Monica Prasad, a professor of sociology at Northwestern University. She says that homeownership is a "lynchpin for the long-term distribution of resources," working in many ways as a replacement for the welfare state. The monetary value of the home is key not only for its own sake, but also for the quality of the education it provides access to. Additionally, home equity credit lines have become a key way for Americans to bear the cost of crises, like covering medical debt. Given the far reaching impacts of home value, this creates a natural incentive for homeowners and the government that likely influences policies seeking to protect property values to be as widely implemented and defended across the country as they are.
Increases housing costs and decreases housing supply
Single-family zoning both increases housing costs and decreases the number of available units by reducing the number of units that can be built on a piece of land. As an example, an old, run-down, single family home on a typical lot in Washington, DC, would sell for about $1 million, but if it were legal for a developer to build a three-story, six unit condominium building on that lot, those units would sell for about $600,000; which is 40% less per unit and 500% more units.
Racial segregation
In the 1970s, the American suburb became a new battleground for civil rights advocates. The standard American suburb was zoned to limit dense housing and rarely encouraged housing developments attainable for less affluent groups. Activists and scholars argue that these policies were borne out of racist motivations—fears of increased crime and property value degradation, as well as the preservation of "community character" were core rationales of suburbanites for these policies. These fears align with some of the driving cultural forces behind White Flight and suburbanization, with industrialization making cities more dangerous.
According to Sonia Hirt, zoning for detached single family homes in the suburbs provided upwardly mobile Whites more space to raise children in, and prevented the "moral corruption" that more diverse cities risked. Additionally, surrounding these homes with more like them prevented the existence of adjacent businesses that might bring types of people—primarily ethnic minorities and the poor—to the suburbs that these residents wanted to avoid. Since those excluded by these policies inherently could not afford to live in these communities, they lacked the franchise and political capital to secure enough influence to change these policies. Scholars argue that the economic segregation of living spaces deprives those in poor locales of economic opportunity and condemns them to being stuck in areas of concentrated poverty. At the same time, suburban residents get separated from racially-diverse urban areas and thus feel a decreased sense of responsibility for the issues contained there.
A 2020 study from UC Berkeley stated "The greater proportion of single-family zoning, the higher the observed level of racial residential segregation."
Political culture According to Sonia Hirt, zoning, as opposed to centralized city planning favored by most other countries, grew popular in the US because of the opposition to state intervention prevalent in American politics. Zoning limits the need for bureaucrats by creating broad land-use guidelines for the private market to follow, rather than directing specific developments under centralized planning. Additionally, arbitration of disputes is largely left up to judicial system, a more popular institution among Americans, rather than through municipal officials.