Shaping America’s Towns and Cities

Zoning refers to a broad set of regulations governing how land may be used and developed. Euclidean zoning, the most common and broadly applicable form of zoning, separates residential, industrial, commercial, and other land uses. Zoning restrictions may, however, be far more narrowly tailored, restricting the height of buildings, how far buildings must be set back from the street, and development density. Taken together, these rules influence where homes and jobs are located, what they look like, and how neighborhoods evolve over time.

Zoning ordinances became commonplace during the early twentieth century. Before modern zoning, American cities generally regulated land use through nuisance laws that enabled property owners and users to sue to bar nearby activities and land uses that limited enjoyment of their land. Throughout the early twentieth century, many landowners sued state and local governments seeking to block the enforcement of zoning laws. In the landmark case of Village of Euclid v. Ambler Realty Co., the U.S. Supreme Court held that local zoning ordinances are generally permissible under the expansive regulatory powers afforded to states by the U.S. Constitution.

Recently, several states have limited, or seriously considered limiting, local governments’ ability to implement single-family zoning—policies that bar the construction of so-called “missing middle” multi-family housing units, such as duplexes, apartment buildings, and condominiums. As of 2023, roughly 75 percent of American urban and suburban land was zoned exclusively for single-family homes. Similarly, advocates call on states to prevent local governments from mandating large lot sizes that may prevent homes from being developed on smaller, more affordable lots. Most American municipalities currently maintain minimum lot-size ordinances.

Zoning proponents argue that land-use regulations help maintain civic order, preserve community and environmental resources, and direct resources where they are most needed. Calls to preserve zoning are not without grassroots support. Many homeowners, and homeowners’ associations who voice support for existing zoning schemes—sometimes pejoratively called “NIMBY,” a play on “Not In My Backyard”—are doubtlessly concerned with maintaining their home prices, they are, however, also powerful voices for environmental protection and historic preservation.

Reformers, however, highlight zoning’s historical role in racial and class-based segregation and contend that modern zoning practices create insular communities, unfairly prioritize certain lifestyles, and unnecessarily complicate home building, raising housing prices. Grassroots groups of so-called “YIMBYs”—a play on “Yes In My Backyard”—advocate for less restrictive zoning practices, streamlined housing permitting, greater housing density and improved walkability, and planning that allows for more mixed-use neighborhoods.

In today’s Saturday Seminar, legal scholars and urban planners discuss the merits and legal complications of zoning reform efforts.

• In an article in the Georgetown Law Journal, Suffolk University’s John Infranca traces legal arguments offered for single-family zoning. He explains that early proponents justified single-family districts as components of comprehensive, city-wide plans well within states’ regulatory powers. Infranca notes that early pro-zoning advocates argued zoning merely consolidated state powers previously exercised through nuisance laws, streamlining the process by allowing cities to head off issues and prevent nuisance suits. Infranca argues, however, that few contemporary zoning measures are part of comprehensive plans, weakening the original justification for single-family districts and bolstering reform efforts. Finally, he highlights the shifting political and legal landscape, cataloging reforms such as California’s legalization of accessory dwelling units and Maine’s 2022 reforms permitting duplexes statewide.
• In an article in the Georgetown Environmental Law Review, Touro Law’s Michael Lewyn proposes eliminating density restrictions where residents can use non-automotive transportation, or abolishing them entirely. Lewyn notes that a few high-cost areas—home to only 13.8 percent of Americans but 45.7 percent of the nation’s homeless—illustrate the urgent need for more housing in in-demand regions. Because low-density development encourages driving, Lewyn contends that dense communities are essential to reduce carbon emissions. He notes that municipalities can thwart regional reforms heightening the need for comprehensive action. Lewyn questions whether modest recent reforms, which often only legalize duplexes or triplexes, can expand housing supply enough to meaningfully decrease housing costs, and, instead, calls for wide-reaching bans on density restrictions.
• In an article in the Boston College Law Review, Brian Connolly, of the University of Michigan,argues that single-family zoning reform alone cannot solve America’s housing crisis. Connolly notes that despite reforms allowing missing-middle housing in formerly single-family zones, production of multi-family housing is impeded by private restrictions baked into homeowner association bylaws and residential deeds, complex building codes, and financing challenges that often make small-scale development economically infeasible. Connolly explains that one-off duplex or triplex projects in existing neighborhoods face higher per-unit costs androduce fewer units than larger projects. Connolly contends that expanding multi-family zones, streamlining permitting procedures, and encouraging income-restricted housing through meaningful density bonuses could produce housing at the scale and pace necessary to address affordability.
• In an article in the Vanderbilt Law Review, Michael Wolf, of the University of Florida,argues that abolishing zoning would maintain its worst features while erasing some of its benefits. He then analyzes existing zoning alternatives—such as Houston’s covenant enforcement system—and concludes that, absent zoning, wealthy homeowners would devise new tools to exclude lower-income residents, including strengthening private covenants, expanding nuisance law, and manipulating building codes. Instead of abolishing zoning, Wolf proposes enacting state laws to bar local bans on renewable energy development, streamlining permitting for missing middle housing, allowing lower-intensity uses within areas zoned for higher-intensity uses—for instance, allowing housing within industrial zones—and eliminating restrictions on manufactured homes such as mobile homes.
• In a forthcoming article, the University of Colorado’s Jaehee Song compiles a nationwide dataset of minimum lot size ordinances. Song’s dataset covers more than 52 million homes across 16,217 municipalities. Song analyzes the dataset against housing cost data and finds that doubling minimum lot sizes may increase home prices by 14 percent and rents by 9 percent. Song likewise finds that larger minimum lot sizes deter non-white buyers: his analysis suggests that doubling minimum lot sizes produces a two-percentage-point rise in the non-Hispanic white share of homeowners and an 11 percent increase in median homeowner income. Song attributes 78 percent of these effects to the direct impact of zoning, demonstrating how zoning laws exacerbate residential segregation and housing affordability challenges.
• In an article in Town Planning Review, urban policy advocate Cameron Murray and Peter Phibbs, of the University of Sydney, challenge claims that planning and zoning impose high economic costs, arguing that popular approaches to measuring the cost of zoning often rest on questionable assumptions. Murray and Phibbs caution that observed price increases may reflect amenity changes and market dynamics rather than changes in regulation alone, and they highlight how other, more dynamic, supply models may better explain counterintuitive correlations between new supply and higher prices. The authors conclude by urging city planners to consider locality-specific market conditions and to compare housing markets across similar cities with different regulatory regimes before inferring causality.