A Brief History of Zoning

TO UNDERSTAND HOW ZONING doesn't work, we need to start with how it is supposed to work—or how it was supposed to work when it was shiny and new. We also need to understand how it has already been modified to deal with new problems and pressures. We need not explore the history in detail—several good books already do that—but we do need to understand today's starting point so we can avoid repeating the mistakes of the past. By reviewing how we have already tried to "fix" zoning, we can identify what parts of the fix worked and what parts did not (and why).

"Euclidean" Zoning

Traditional zoning is "Euclidean" zoning, named not after the Greek mathematician Euclid nor because a zoning map looks sort of geometrical, but after the town of Euclid, Ohio, which won the first lawsuit over the legality of zoning. But before Euclid there was New York City, which adopted the first major zoning ordinance, in 1916. If you can imagine the chaos of New York during the early twentieth century, when it was bursting at the seams with more poor immigrants arriving daily, you can understand why the city leaders felt they needed to do something. They had already adopted a partial building code (the Old and New Tenement Laws) requiring that apartment houses be built so that a certain amount of light and air could reach the inner rooms. But now those tenements were sprouting up everywhere, even near factories—and, worse yet, near mansions.

So New York City adopted a "zoning plan" restricting the uses to which land could be put. Basically, they divided the city into "zones" for residential, commercial, and industrial uses. While they were at it, they also established an imaginary box within which buildings had to be built on each site. Some parts of the box—for example, requirements for access and light—were simply concepts carried over from the Tenement Laws of 1867, 1879, and 1901. The sides of the box were defined by distances that the building had to be "set back" from the front, rear, and side lot lines, and the top of the box was a maximum height limit on the overall structure. That was it. There were no parking controls (not many cars back then), no sign controls, no landscaping requirements, and no design controls. This was the backbone of zoning: a division of the city into use zones and boxes into which buildings had to fit in order to avoid crowding their neighbors; to avoid creating public health, safety, or fire hazards; and to prevent land use combinations likely to cause nuisances in the future.

The structure of the zoning document was straightforward. It included one chapter for each zone, with a narrative list of permitted uses and a list of setbacks and height limits. A separate chapter described the procedure for amending the zoning text or the zoning map. Importantly, we could change the text without changing the map (everyone in the affected chapter now had new rules for the future), and we could change the map without changing the text (owners in the recolored area now just followed a different set of rules). This is important, because this book is about changing the text of the zoning ordinance—not the map that applies it to specific parcels of land in the city.

Of course, even back in 1916, people were smart enough to know that no rule will work perfectly. For example, there may be parcels of such a weird shape that they physically cannot meet the setbacks, or instances where the height limits make no sense because the property is in a valley and the surrounding buildings would tower over it. So they allowed for "variances," which required an appearance before a "board of adjustment" to show that yours was a unique situation created by history, or by the land itself, and not by you yourself. You also had to show that, because of that uniqueness, applying the rules rigidly would produce a result that was unnecessarily harsh on you and that flexing the rules for you would not create significant problems for your neighbors. If you created the problem yourself (for example, by selling off some buildable parcels in a way that left you with an unbuildable one, or because you just paid too much for the land and you needed a taller building to break even on the deal), then tough luck. You couldn't create a problem and then ask your neighbors to bear the burden of fixing a problem you could have avoided. This was all very logical and straightforward—a set of simple rules and a way to make exceptions in unique circumstances.

These basic Euclidean zoning tools did not change much until after World War II. The structure of the system was robust. We could do a lot with it. The original New York system had three colors—residential, commercial, and industrial—but there was no reason it could not have six colors, or twelve, or twenty. Instead of a "business" zone, you could have "business 1" and "business 2" zones to cover different types and scales of building. If you wanted a residential zone where the uses and boxes would allow only single-family houses, just create one and recolor a part of the zoning map to the new color. If you wanted a residential zone that makes each box sit far from the others—in effect requiring larger lots and encouraging more expensive houses—just create one. If you wanted to have one zone for heavy (smelly and smoky) industry and another for light (clean and quiet) industry, create them.

So Euclidean zoning remained largely unchanged in concept, but it became more complicated in practice. Denver adopted its first zoning ordinance in 1923 and its second ordinance in 1957. Table 1.1 shows how the menu of districts within the city changed over time. Not only were the basic categories (residential, commercial) being sliced into more varieties, but entirely new types of zones appeared.

Zones typically are shown on maps in different colors—lots of them. Residential zones are often shown in yellow, so as residential zones multiplied, we could use dark yellow and then light yellow and then lemon yellow. Anyone with a computer monitor knows that there is no shortage of different colors out there—but there is a limit to how many variations of yellow the human eye can distinguish when they appear next to one another on a map. Multifamily residential is often shown as somewhere between yellow and brown, but not all of us can spot the difference between dark orange, rust, and burnt sienna without constantly referring back to the map legend. So even though each new zone could have its own color, both the public and the planners sometimes had trouble keeping track of what the different colors meant. This foreshadows one structural problem in thinking of each zone district as a world unto...