America’s Zoning Problem: Implications, Legacy, and a Path Forward

Updated: Mar 30, 2021

What is Zoning?

In American metropolitan areas, growth and development are contingent on a collection of rather arcane municipal laws and regulations commonly known as zoning. Zoning is a method of urban planning in which the government subdivides land into districts, which fall under distinct sets of requirements and limitations that impact everything from structure heights to signage. However tedious, zoning is key to understanding many housing and broader socio-economic issues pervasive throughout the country. An underlying goal of Nesthubs is to address problems associated with zoning and to educate and engage communities in zoning policy.

The Zoning Map and Ordinance

Zoning consists of two fundamental elements, the map and zoning ordinance. The map divides the land of a given area into color-coordinated districts known as 'zones,' which are also denominated by a zoning code. All zoning codes are listed in the zoning ordinance, where the regulations and permitted uses are specified and displayed in a table or appendix. Cities locally manage their zoning policy but commonly use similar zoning types such as yellow for residential, red for commercial, gray or purple for industrial, blue for institutional (public buildings), and green for open space.


Figure 1 shows a zoning map from the city of Atlanta (not the full metro area), with most of the zones in yellow for residential. Along with the standard colors and ordinances explained above, this example map has orange zones for Planned Unit Development (PUD), which allows varied and compatible land uses, such as housing, commercial centers, recreation, and industrial parks. Many zoning maps, including Atlanta's, also distinguish between the intensity of uses. Zoning codes containing the same letter (e.g., R1, R2, R3...) represent types of permitted uses with the increasing numbers correlating with increasing density levels (dwellings per lot size). In addition to laying out the basic permitted uses and density, the ordinance sets detailed development standards for yard setbacks, minimum lot sizes, and building heights. A zoning ordinance can also include more complex regulations, including conditional or special zone classifications, which require additional consultations and approvals from the city's local government. More broadly, ordinances contain impact regulations not specific to one district, such as signage, parking standards, historic preservation standards, and urban design criteria. Citizens can learn more about their city's zoning map and ordinance by reaching out to the local government or searching on their urban planning municipality's website.

Why Does Zoning Matter?

Today, zoning's commonly cited purpose is to ensure that new developments are built responsibly and minimize the impact on adjacent property owners. For example, zoning can protect a neighborhood of single-family homes from having hazards such as oil refineries built nearby. With this benefit, it is clear why cities have utilized zoning for over one hundred years. However, there are many negative aspects to zoning, and civic leaders and community members have begun questioning the practice. First, communities can use zoning practices as a tool of exclusion. Historically, this happened explicitly with zones that prohibited citizens from districts based on skin color or ethnicity. When this practice was deemed to be unconstitutional and removed, explicit exclusion gave way to implicit exclusion still relevant today. A modern practice to zone communities out of areas is by imposing large, minimum lot size requirements and other regulations that increase the cost of building a home. When new homes require a one-acre minimum, larger, more expensive homes are incentivized. In this way, cities can become enclaves for the rich at the expense of low and moderate-income families. The second major criticism comes from the segregation of zoning uses. As mentioned before, the segregation of allowed uses can help protect neighborhoods from large commercial developments. However, segregating uses can also lead to sterile environments that require citizens to travel large distances between different zones for trips to work, school, and shopping. At Nesthubs, one of the main barriers to achieving the organization's goal of creating affordability in Atlanta is the excessive use of a zoning type referred to as single-family zoning.

Single-Family Zoning

Single-family zoning (commonly known as R1 in planning parlance) is an ordinance that prohibits residential dwelling types except for detached, single-family homes. This falls under the broader term of low-density residential, 'low-density' referring to the larger amount of area generally required per residential dwelling as compared to multi-family residential. The single-family home is ingrained in American culture and psyche and is ubiquitous in the country's suburban areas. However, many urban areas have also been zoned exclusively for single-family and low-density residential. Nesthubs seeks to build the case that single-family zoning should be diminished, particularly in emerging economic hubs such as Atlanta, where about 60% of the land is zoned for single-family residential (Atlanta City Design Housing). Other metros (metropolitan areas) may have upwards of 80% single-family zoning. This excessive use of single-family zoning stifles innovation and consumer choice, perpetuates social and economic segregation, and damages the environment.

Consumers Should have Options

Many defenders of single-family zoning have long implied that restrictive zoning policy is necessary for metros to protect suburban families and the backyard space deemed ideal for families raising children. However, the notion that single-family housing with yards should be made available is not the same as mandating most of a city's land area for that purpose. Though many residents are attracted to single-family homes, housing preferences are diverse and often changing. Residents without children, such as young people and the working-class, have less need for a multi-bedroom house with a yard and would be better served by a market offering more options. Additionally, families in the United States and worldwide have shown interest in raising children in dense cities. In New York City alone, there are over one million students in New York City public schools, many of whom live in apartments, condos, and townhomes. Zoning has also constrained consumers' choices and imagination. Since it has been around for so long and employed so widely, single-family homes and apartment living are all that many urban citizens know. The over enforcement of single-family zoning has stifled innovation seen in other industries and restricted consumer choice. Losing single-family zoning restrictions is not about changing people's preferences; it is about expanding their options beyond single-family houses.

The Alternative: Middle Housing

It is important to highlight that housing at different densities does not translate to developers building high-rise housing in residential areas. In fact, high-rise housing is often built because the amount of land zoned for multi-family housing is so constrained that developers build upwards to maximize that scarce resource. In cities with less mandatory R1 zoning, such as many of those in Europe, you will not find a significant presence of residential skyscrapers but rather mid-rise buildings and townhomes that achieve higher density while remaining aesthetically pleasing.

Figure 2: Number of Units per Zone in Atlanta (2010-2019)

Source: ASS 1-Year Estimates (2010-2019), Atlanta Department of City Planning

In Figure 2, you can see that most of Atlanta's zones consist of single-family units (1 unit), followed by properties with over fifty units, exhibiting a bifurcated market of either high-density or low-density structures. American zoning practices contribute to this dichotomy and leave out what planners refer to as middle housing, such as condos and micro-unit types like modular housing. In places where middle housing has been built, it has found success; Nesthubs believes there is ample demand for it, but that zoning has constrained supply. When coupling this supply shortage with population increases, the growth of the city is limited. Limited growth areas become pressure points in the supply/demand equation of the housing market. When too few housing opportunities exist for an increasing number of residents, residents with the greatest economic means begin to drive out those with the least economic agency.

Single-Family Zoning’s Exclusionary Legacy

Regardless of any preconceived advantages concerning single-family zoning, its supremacy was not a result of market forces and consumer preferences. Instead, its relevance was facilitated by its historical use as a tool to exclude poor and minority households. After the Supreme Court struck down institutionalized racial segregation in residential areas in Buchanan versus Whurley (1917), zoning practices such as single-family, which allowed segregation by income, began gaining popularity. Single-family zoning created segregation outcomes similar to practices like redlining and exclusionary zoning but in a less explicit manner. The reissuing of Atlanta's zoning ordinance in 1929 perfectly exemplified this phenomenon. Zones that were previously designated as "R-1 White Districts" were amended to "R-1 Dwelling House Districts" and "R-2 Colored Districts" to "R-2 Apartment Houses." The change determined that zoning could no longer restrict areas based on race; however, it capitalized on the economic disparities between races at the time to reinforce racial segregation on a financial basis. White families were the primary landowners, and single-family zoning required new homes to be built on landmasses that only wealthier, typically white families could afford. The segregation effect of the single-family zoning strategy was so severe that the divide remains today.

Figure 3: Relationship Between Racial Diversity and R1 Zoning

Source: US Census, ATL Department of City Planning

Figure 3 shows how, in Atlanta, neighborhoods with the most land reserved for exclusionary single-family housing have maintained low racial diversity levels. Conversely, neighborhoods exhibiting the most racial diversity have a small minority of the area dedicated to single-family homes. This stark negative correlation between single-family zoning and racial diversity is a reminder of single-family zoning's ever-prevalent racist legacy. Allowing more affordable middle housing in these wealthier suburban neighborhoods would allow other demographics to access those opportunities and improve their quality of life. Though the suburbs have become more diverse over the decades, single-family homes in the suburbs are primarily owner-occupied. Minority households are buying homes in the suburbs at increased rates, but white households remain overrepresented in neighborhoods that are segregated by income. Fostering more equitable cities will mean unwinding the existing structures designed to be exclusionary and working together to build new policies that promote inclusivity, resiliency, and equity.

Environmental Impacts

Single-family zoning is one of the least environmentally sustainable forms of housing. R1 requires houses to be separated from other houses on lots, with zoning often mandating large setbacks and lot sizes, reducing overall density, and increasing the amount residents will need to travel in their everyday lives. Internal combustion engine cars are the primary means of transportation in suburban areas, and longer trips mean more emissions. Larger lots also mean that new R1 areas require more space than mid-density housing types like duplexes and rowhouses, leading to neighborhoods that take up more land and transform more natural areas and animal habitats into lawns and driveways. Additionally, the innovative manufacturing and construction costs for newer forms of middle housing such as modular and panelized homes are significantly lower than that of traditional single-family homes. Small detached multi-family dwellings are often referred to as ‘micro-units.’ Micro-units can be partially or fully prefabricated in-house, meaning much of the construction takes place under controlled processes in a factory. By producing buildings in a factory setting, it is easier to control the use of energy compared to an open construction site. Controlled manufacturing conditions maximize efficiency and cut time and waste. Units are transported in one streamlined shipment, and low installation and assembly requirements reduce vehicle movements and on-site traffic. Smaller units are compact and easy to insulate, thus require less energy to run and heat. Micro-units are also easier to recycle at the end of life due to easy structure dismantling, minimizing waste and environmental impact, and modular units, in particular, can be repurposed and resold.

The Path Forward

Several cities have already begun the transition away from single-family-dominated urban planning. Minneapolis has implemented a zoning plan that sets three units as a residential minimum without a single-family home mandate. California recently passed a law in 2019 that allows homeowners to easily build up to two accessory dwelling units on their properties, effectively ending single-family zoning in the entire state. As communities continue to feel the costs of single-family zoning, urban planners will be pressured to embrace this trend towards middle housing. Atlanta made encouraging progress in 2019 with Mayor Lance Bottoms' commitment to the One Atlanta Housing Affordability Action Plan. This plan calls for bold zoning reform to allow more affordable housing types, address inequality issues, and sets the goal to create and preserve 20,000 affordable housing units in Atlanta by 2026. Nesthubs does not think it is a question of if, but rather when US metros will transition away from single-family zoning, allowing for a greater variety of housing types to enter the market. Micro-units are the ideal product to emerge as developers respond to a less regulated market and seek higher density housing types that remain aesthetically pleasing and can offer yard areas. These outcomes increase housing choice and housing supply, which increases housing affordability without making a big difference in single-family zoned neighborhoods' overall character. American metros will inevitably grow, but the growth should be influenced and shaped according to local communities' needs. Citizens can get involved in zoning policy through civic engagement and appeals to their local Department of City Planning. When designed and regulated properly, rezoning initiatives can be powerful tools for shaping cities that promote prosperity, sustainability, and inclusion.

Dylan Butts is the Director of Business Development at Nesthubs where he leads initiatives centered on developing the organization's relationships and outreach, producing research and written pieces, and improving services. He has a background in Economics and Renewable Energy and is passionate about leveraging innovative economic thinking to maximize social advancement.

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