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A Brief History of Zoning

What is zoning?


What is zoning, exactly? Why did it become what it is? Why is it important? Why is it so complex? How do we deal with it today? And how can I learn more?


This is our attempt to provide answers to those questions. It’s called: UrbanForm’s Brief History of Zoning.


It’s organized into three sections:

Zoning defined 


First, let's start with a definition. At the most basic level, in the US, zoning regulates how land can be used.

If we focus on urban areas, zoning can be better understood to govern buildings. Zoning is what can be built and where.

To be even more precise: zoning regulations are spatial and legislative rules that govern what buildings in a certain location may be used for, what form those buildings may take, their density of usage, and often, other things related to building on or using that land (such as parking).

As we can see by the definitions alone, the idea of regulating land use gets complicated quickly. Even from the very outset, zoning in the US has never been without controversy. In fact, the particulars of zoning’s origins (The Constitutionality) explain why the US has a land-use system that is unique, both in terms of the mechanisms of control (The Complexity) and the resulting effects (The Consequences).


Because of this, it can be helpful to start with the origins of zoning in the US.



Of Zoning

The origins of zoning


“Perhaps the strangest thing about the U.S. land-use regulation model is that it exists.”

– Sonia Hirt, University of Georgia

The first zoning ordinances in the US were instituted about a hundred years ago, perhaps modeled after similar ideas from Europe (Germany, in particular), and ostensibly sprang from the intention of protecting the public’s health, safety, and welfare.


One of the first referenced examples of zoning is the 1916 Zoning Resolution of New York City. These city ordinances were reportedly developed in response to the construction of one particular building in downtown Manhattan.

The Equitable Building of 1916. Note the size of the people and cars at ground level to appreciate the size, scale, and bulk of this building. 

In 1913, construction started on the Equitable Building, which rose 42 stories, to a height of 555 feet, covered every available square foot of its property on the ground, and cast a shadow seven acres in size. It blocked sunlight to an adjacent public park for most of the day and completely blocked all access to light for three neighboring buildings.


In response, New York City crafted zoning regulations to mandate that buildings step back their exterior walls from the property lines as they rose in height, modulating their bulk, to allow access to light and air to neighboring properties and the public streets on the ground.


The theory was simple: access to light and air benefits the health and welfare of the people, and buildings should modulate their size and shape for the public good. Zoning, therefore, would be used to protect the health, safety, and welfare of the public. Who could argue with that?

But the 5th and 14th Amendment of the US Constitution states:


“No person shall…be deprived of / nor shall any State deprive any person of life, liberty or property without due process of law. . . Nor shall private property be taken for public use without just compensation.”


After all, the US is the land of the free, where rugged individualism and private entrepreneurship are the fundamental pillars upon which American exceptionalism is built. Restricting what can be done on private property seems to contradict these principles.


By restricting uses, or otherwise regulating what can be done on private property, zoning could be construed to be a ‘taking’ of private property, ‘without due process’ or ‘just compensation,’ as prohibited by the Constitution. And that’s what was argued, all the way to the Supreme Court, in the 1926 case of Village of Euclid v. Amber Realty Co.

Michael Allan Wolf, "The Zoning of America".

This Supreme Court case (which will celebrate its centennial birthday in a couple of years) established the legal basis for zoning as we understand it today in the US.


To summarize Euclid v. Ambler, the conflict was with a company that desired to develop the land it owned for industrial uses versus a municipality that passed a zoning ordinance designed to maintain that area for residential or non-industrial uses.


The Court sided with Euclid, finding that the village ordinance was justified as an exercise of police powers—the constitutionally granted power of the states to regulate for the protection and maintenance of the health, safety, or welfare of its citizens.

Euclid, Ohio

Within this Supreme Court decision, and its dissenting opinions, we can find elements of everything that currently surrounds the issue of zoning today.


From the majority decision:

“. . .the exclusion of buildings devoted to business, trade, etc. from residential districts, bears a rational relationship to the health and safety of the community. . . with the great increase and concentration of population, problems have developed, and constantly are developing, which require, and will continue to require, additional restrictions in respect of the use and occupation of private lands in urban communities.”


Here we see all of the major mechanisms and justifications for zoning as we know it today: the exclusion of buildings by use, justified through police powers at local levels, rationalized in the name of health and safety, with provisions for additional restrictions as deemed needed to manage urban environments.


But the judicial dissent also portends to what we now understand about zoning as well:

“In the last analysis, the result to be accomplished [by zoning] is to classify the population and segregate them according to their income or situation in life."


This is what we now call ‘Euclidean’, or exclusionary, zoning; the establishment of geographically delineated areas of excluded uses, in reference to the Supreme Court case of Euclid v. Ambler, 1926 (and not, confusingly, to Euclid, the ancient Greek mathematician and founder of geometry).

Euclid, the ancient Greek mathematician and founder of geometry. Euclidean zoning is NOT about this person. 

From this origin has sprung an incredibly complex system of legal, spatial, economic, and other mechanisms to control ever more minute details of the built environment.


That's what we'll be discussing in the next part of this Brief Introduction to Zoning.



Of Zoning

The complexity of zoning

“Both building regulations and zoning were born out of concerns for public health: clean water, fresh air, effective sanitation, and so on. But political expediency and outmoded planning concerns drove many early regulations, and jurisdictions have spent a century applying band-aids to problems. We now have massively complicated regulations running to thousands of pages in length that require an army of experts to interpret and implement.”

– Paddy Tillett, Principal and Director of Planning and Urban Design at ZGF Architects.

1920-22 Map of Euclid, Ohio, with the Ambler property in the top middle portion

Zoning in the US, as established in Euclid v. Ambler, generally groups land uses into the familiar, broad categories of residential, commercial, industrial, and agricultural. The Village of Euclid originally proposed a zoning system based on six different use classes and 3 different height classes.


Today, however, the uses allowed or prohibited are often embarrassingly specific. For instance, the City of Seattle explicitly allows or prohibits in certain zones “Railroad switchyards with a mechanized hump”, or “adult cabarets,” among 122 different use categories.


Crucially, an early distinction was made between single-family residential uses and multi-family uses (such as apartment buildings, townhouses, or other housing typologies). This distinction, according to authors such as Sonia Hirt and William Fischel, is perhaps the primary reason for the distinctly American consequences that currently surround zoning. This will be discussed in the third installment of this series (The Consequences of Zoning).


Even the first zoning ordinances that attempted to manage building form, such as the 1916 New York City zoning ordinance, were already quite complex. Remember, this ordinance was developed in order to prevent buildings of the size, scale, and shape exemplified by the Equitable Building. So formulas were used to mandate required step-backs at certain heights, giving rise to the famous ‘wedding-cake’ shape of NYC’s skyline.

A diagram illustrating early NYC setback rules

Hugh Ferriss illustration

The New York City skyline, with its distinct zoning-derived 'wedding-cake' silhouettes

The formulas were complicated enough to prompt the commissioning of an illustrator, Hugh Ferriss, to help communicate the consequences of these rules. These illustrations were made famous by the book The Metropolis of Tomorrow, published in 1929.


Today, the methods developed to regulate building form are familiar to any architect. Height limits, setbacks/stepbacks, allowable ground coverage, maximum footprints, sloped planes, and other spatial constructs are all part of the zoning parameters that need to be discovered, calculated, modeled, and verified in order to design compliant buildings.


The density of building is also often regulated by specifying the minimum and the maximum number of dwelling units and the number of stories allowed. Allowable floor area is often expressed as a formula related to the size of the property, called floor-area-ratio (FAR).


This list of spatial rules is by no means exhaustive, and ever more specific mechanisms for controlling buildings are constantly being developed.

Diagrams illustrating various building regulations from the NYC Planning Dept

By combining land use regulations with other building restrictions, such as the formal regulations exemplified by the NYC zoning (sometimes called ‘development standards’), we arrive at what is commonly called ‘comprehensive zoning.’


Comprehensive zoning also governs things on or near buildings related to the urban environment, such as parking, landscaping, signage, canopies, and light fixtures, among many other things. Performance metrics for traffic, noise, pollution, and other things are also often regulated. 'Inclusionary zoning' was invented to require certain types of housing be built, usually low-income or below-market-rate. Incentives, or bonuses, also become a common mechanism within zoning to allow modified building parameters in exchange for public amenities, such as affordable housing, park space, sidewalk or utility improvements, contributions to municipal funds, or other such concessions.


In the latter part of the Twentieth Century, partly in response to the perceived inadequacy of zoning on different levels and inspired by the thinking of Christopher Alexander and the New Urbanists, form-based building codes were developed. Form-based codes layered much more stringent and prescriptive building form regulations, on top of or blended with Euclidian use-based zoning, in the hopes that more and stricter regulations would better “foster predictable built results and a high-quality public realm by using physical form as the organizing principle for the code.” (

An example of implemented form-based codes from

Put all these land-use regulatory concepts together and you start to get a glimpse of The Complexity of Zoning, which is an inescapable feature of our building culture and built environment today in the US.


This Complexity means that a basic understanding of what you can build on a piece of land is actually really hard to come by. Layers of legislation on different aspects of the built environment keep being added; rarely do local political processes lead to reduction and simplification.


But there may be an even simpler and more effective way of giving people a glimpse into The Complexity of Zoning; by looking at how municipalities rule over something as simple as a parking spot.

If anyone doubts how complicated the rules for building could become, then the image above should put that doubt to rest.


And from here, it's also easy to see how a little bit of technology could go a long way towards making people's lives a little bit better. This is what UrbanForm does for the rules of zoning.


Zoning’s complexity is a direct result of the mashing together of US legislative processes and rules for the organization of urban space. Each on its own is complex enough; any architect knows that organizing, communicating, and documenting spatial ideas is hard, and any politician knows that balancing competing interests to write laws is no easy battle.


Zoning is both; it is the legislation of space, using the political process to manage buildings, space, and urban environments, by adopting ever more specific mechanisms, while balancing the many needs of both the public and the private.



Of Zoning

The Consequences: Macro-effects

“We’ve long known two things about land use regulations. One is that . . . ‘exclusionary zoning’ has led to racial and economic segregation. The other is that restrictive land use and building codes in cities limit housing construction (and therefore housing supply), leading to increased costs, worse affordability problems, and deepened inequality in urban centers.”

–Richard Florida, University of Toronto


While zoning may have originated from an intent to promote health, safety, and welfare, those issues were not always the primary motivation for how it has developed in the years since. This was foreseen as early as in the original dissenting opinions in Euclid v. Ambler.


Entire books have been written about the consequences of zoning, but the effects that are discussed the most today center around two issues: segregation and housing affordability.


Historically, the use of zoning to racially segregate cities is particularly breathtaking, and books by Sonia Hirt, M. Nolan Gray, and others serve as good introductions to this incredibly complex topic.

Image credit: Neal Gorenflo, via Shareable, which has a great blog post on books/studies of the racial effects of zoning

The economic segregation of cities (which is related to racial segregation), is probably best introduced by William Fischel and his many books, the most recent and popular of which is Zoning Rules! The Economics of Land Use Regulation.

Constraints on housing production directly impact housing affordability, and zoning plays a large role in constraining production, either directly by excluding certain building types, or indirectly, through The Complexity of Zoning. The contemporary YIMBY (Yes in My Back Yard) / NIMBY (Not in My Back Yard) debates are a testament to this ongoing debate over allowable housing products in certain areas. The long wait times for land-use reviews at building departments, and studies linking those delays to housing costs, is testament to the indirect effects of Complexity.

Photo via Placesense / David Jenkins

Housing affordability, and the debate over its causes and how to best address it, is beautifully introduced by Coby Lefkowitz in his recent blog post, “America’s Affordable Housing Problem: How America got to be so unaffordable, and what we can do to make it more affordable; an analysis of good-in-theory v. outcome based policies.”


Those writings serve as great introductions to the larger, macro-effects of our zoning system today.

The Consequences of zoning:

Practical considerations

More practically, the process of acquiring accurate zoning information is something that must be undertaken for every single construction project in the US.


Architects, developers, contractors, and many others rely on this information to understand the regulations that govern construction on everything from fences, decks, and ADUs all the way up to multi-family apartment buildings and skyscrapers.


Remember, zoning is composed of a complementary set of maps and text.


Because of The Complexity of Zoning, the process of acquiring it is time-consuming, labor-intensive, and error-prone. It requires consulting all the maps and the collected ordinances/texts that make up the comprehensive zoning code for whichever jurisdiction has authority at any particular site.


The maps have gotten more and more complex, and one single site may require consulting dozens of different maps to understand all the applicable regulations.

A lower Manhattan zoning map, via New York City Department of Planning

The text itself has gotten longer and longer and requires the comprehension of not just dense legal language but the deciphering of relevant tables, charts, and diagrams.


For instance, in Portland, Oregon, the zoning code went from 250 pages in 1979 to over 1,800 pages today (the image used at the title of this post shows the binders containing the Portland Zoning Code, as of 2016). And that number does not include the maps, nor the commentary, guides, explanations, and other addenda that are regularly issued to support and complement the text itself. To further complicate matters, all of this information is kept in non-standardized formats, scattered in different locations, along with legacy versions or archives, and managed by each municipality completely independently.

As an example, the image above is a screengrab from the instructions for how to properly acquire complete zoning information from the City of Portland, as written by the City itself, in the first pages of the zoning code. There are more than 7 discrete, sequentially dependent steps. To thoroughly follow this procedure can take days, even for an experienced professional. In practice, it is not uncommon for this process to take weeks.


The Complexity of Zoning is part of the reason why it takes so long to get a building permit. In Seattle, it now takes an average of 2.2 years to get a building permit, of which 1/3 of that time is spent conducting land-use review.


This has a cost; in fact, it’s been estimated that up to 42% of the cost of a single unit of housing is attributed to regulations including zoning. That’s almost half the cost of new housing.


In short, The Complexity of Zoning has Consequences.

Solving Complexity with UrbanForm

This is what UrbanForm was built for; to solve The Complexity of Zoning so that we might better manage The Consequences.


The goal of UrbanForm is to provide accurate, efficient, and verifiable zoning information to architects, developers, and contractors; managing their process of acquiring zoning information and allowing them to spend their time and energy solving other problems in the built environment.

UrbanForm automatically isolates the relevant regulations, hides the irrelevant ones, calculates the spatial formulas, gathers and documents the sources, and makes it all accessible from a single point of access, available anywhere with an internet connection and a web browser.


With UrbanForm, it no longer takes days, or even weeks for a building professional to acquire zoning information, it takes seconds. UrbanForm is one digital process that replaces a hodgepodge of manual and analog processes.


We do this by using software AI, in conjunction with teams of analysts with degrees in architecture and urban planning, and the continual training, iteration, and improvement of our AI software through customer feedback.

UrbanForm is currently available in Seattle, Portland, and San Diego. More cities are coming soon

We are not going to tell you that UrbanForm is perfect. It’s not a silver bullet that will usher you straight through the issuance of a building permit (we’re working on that). And it's only one piece of the vast puzzle that needs to fit together in order to make any one building happen, let alone a city. But it’s already much, much better than the alternative. And it’s going to continue to get better.


UrbanForm’s customers are architects, developers, and contractors. These are the professionals who create the buildings and cities where we spend most of our lives. There are a lot of problems to address in our real, built environment, and that is why UrbanForm is dedicated to supporting these professionals.


We can’t put money in their pockets. But we’re doing the next best thing, by providing a tool that will save them time, allow them to focus on doing better work, and address the larger issues that will allow them to flourish. And our belief is that our built world will flourish as a consequence.

An all-staff meeting at one of UrbanForm's customers, Bora Architects

Architects currently make up our largest customer segment. That’s how you know that UrbanForm works. Architects are typically responsible for getting the zoning information correct, and their professional livelihoods are at stake. It’s not something that we take lightly.


We’re proud to partner with these professionals to make sure that as much energy, attention, and effort is spent making the best buildings and cities possible.


That’s UrbanForm’s mission: better buildings and cities.

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