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Single-Family Zoning Linked With Income and Race Segregation

An analysis of zoning laws in Connecticut finds people in single-family areas are likelier to be white and have higher incomes than those in areas that allow more housing. The findings add to a growing recognition of how zoning is linked with segregation and exclusion.

Aerial,View,Of,Suburban,Development,And,Real,Estate,In,Milford
An aerial view of Milford, a suburban town in Connecticut. Single-family housing is the only type of development that’s allowed on 62 percent of land in the state.
(Shutterstock)
In Brief:
  • A new report from the Urban Institute presents a “fine-grained analysis” of zoning rules in Connecticut.

  • It finds that single-family housing is the only type of development allowed on about 62 percent of state land.

  • Single-family areas are associated with higher home values, higher median incomes and greater proportions of white people than other areas, according to the report.


  • It’s legal to build a single-family house on more than 90 percent of land in Connecticut. But building an apartment with three units or more is only allowed on 2 percent. That imbalance is associated with significant disparities in race and income across Connecticut’s different communities, according to a new report from researchers at the Urban Institute and Cornell University.

    The report, published this week, is called Bringing Zoning into Focus: A Fine-Grained Analysis of Zoning’s Relationships to Housing Affordability, Income Distributions, and Segregation in Connecticut. Researchers matched data about population demographics and home values with an atlas of all of Connecticut’s zoning codes to explore how single-family zoning is linked with race and income exclusion. They found that people living in areas with the most single-family zoning are much likelier to be white and to have significantly higher incomes than people who live in areas where multifamily housing is permitted.

    Concluding that “strict zoning regulations … are associated with inadequate access to affordable housing and with the segregation of people by income, race and ethnicity,” the report could add support to a growing movement to loosen zoning regulations in communities across the United States.

    Neighborhoods comprised of single-family homes on their own properties make up much of the urban and suburban U.S. But in the last half-decade, more cities and states have seen movements to undo some of those regulations. Some opponents of strict single-family zoning restrictions argue that they increase housing costs by artificially limiting the amount of housing that can be built in a certain area. Others note that they reinforce patterns of racial segregation in neighborhoods — a dynamic that was actually the intended effect of many early zoning ordinances. The new Urban Institute report, the first to analyze every zoning code in an entire state, bolsters some of those arguments.

    “Single-family zoning policies are part and parcel of a system of local exclusion that discourages integration and supports the ability of wealthy, white, well-educated homeowners to live in neighborhoods largely constituted of similar people,” says Yonah Freemark, a senior research associate in the Metropolitan Housing and Communities Policy Center at the Urban Institute and co-author of the report. “We suspect this holds true in many other states across the country.”

    Zoning can be used to regulate many aspects of the built environment, from lot sizes to building height and parking requirements. The report focuses on one of the simplest and most common provisions of zoning codes — the number of dwelling units they permit on a given property. The researchers analyzed code requirements that restrict development to single-family housing only versus those that allow up to two, three or four units and more. Single-family housing is the only type of development that’s allowed on 62 percent of Connecticut land, they found. And it’s concentrated more in suburbs in towns than it is in the state’s eight biggest cities and rural areas.

    In all areas of the state, single-family zoning is associated with higher home values and higher median incomes than zoning that allows four or more units, according to the report. In addition, “zones allowing only single-family construction have a much higher white population share in the big eight cities, suburbs and towns than the neighborhoods zoned to allow construction of buildings with four or more units,” the report says. These findings comport with the increasingly common recognition that zoning is linked with segregation and exclusion, Freemark says.

    “We can’t hide behind the veneer of not knowing or not being sure, because we’re able to look at the data. People are segregated, to a large degree, on zoning-based lines,” he says.

    The report also finds, somewhat counterintuitively, that despite higher home values in single-family areas, cost burdens for renters are actually highest in the most densely zoned areas. Rental cost burden is a measure of how much of a tenant’s monthly income is spent on housing. Renters are likelier to be cost-burdened in areas that are zoned to allow multifamily dwellings. The highest share of cost-burdened renters is in dense urban areas that allow four units or more.

    One potential explanation: median incomes are lower in those areas in general, says Lydia Lo, a research associate at Urban who co-authored the report. Another is that, given how little land is zoned for multifamily housing in Connecticut, there may be “pent-up demand” for apartment living in walkable urban neighborhoods that are close to lots of amenities.

    “There’s not very much rental housing, period, and it certainly is not distributed equally across the state,” Lo says.

    The report is part of a growing body of research on how zoning intersects with economic and demographic patterns. While it’s increasingly clear that single-family zoning is linked with segregation and exclusion, it’s less evident how effective zoning reform is at promoting affordability and integration. A previous Urban report published this spring, which Freemark and Lo co-authored with a larger group of colleagues, found that upzoning was associated with small increases in housing supply but not with reduced housing costs.

    The Connecticut Zoning Atlas that underpins the research is also part of a bigger effort to create a national zoning atlas, which would allow researchers to analyze a wide range of zoning impacts on a much greater scale, says Sara Bronin, a professor of city and regional planning at Cornell who co-authored the report. Researchers have often been confined to a single jurisdiction when trying to study the impacts of zoning rules, she says. The statewide analysis for Connecticut, which links demographic and economic data with zoning rules for every part of the state, could be repeated in other states as more parts of the atlas are filled in. It could add understanding into hot debates about how zoning is linked with affordability and exclusion, but could also help policymakers make decisions about things like small-business development and climate adaptation.

    “Hopefully this report will influence legislators to take a hard look at the way zoning works in our communities,” Bronin says.
    Jared Brey is a senior staff writer for Governing. He can be found on Twitter at @jaredbrey.
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