Decoding Zoning

By Karina French1

As part of our racial segregation report series, we mapped exclusionary zoning, analyzed its association with racial segregation in the Bay Area, and offered recommendations for exclusionary zoning reform. However, the path to effective zoning reform is still emerging, as only a handful of cities nationwide have moved towards reforming single-family exclusionary zoning. This article describes the statutory basis and process of amending zoning law in California, offers a framework for understanding the phases of reform, and provides examples from California and beyond. The accompanying spreadsheet (Policy Reform Tracking Spreadsheet) provides a review of current, completed or ongoing reform efforts.

Zoning Authority

Zoning is the legal mechanism by which government entities control development on land within their jurisdiction, primarily by designating land for certain uses or categories of uses (zones). The practice of zoning emerged in the late-nineteenth and early-twentieth centuries, but proliferated in the 1920s and 30s after the United States Supreme Court affirmed municipalities' constitutional authority to regulate property through zoning ordinances in the landmark case of Village of Euclid v. Ambler Realty Co.2 “Euclidean zoning,” which defines parcels based on distinct residential or industrial/commercial use, became ubiquitous in the US.

Although the earliest zoning ordinances were designed to regulate racial residency or businesses run by racial minorities,3 Euclidean "use" zoning ostensibly began as a way to mitigate negative effects of industrial and urban development (light and air pollution) on residences by separating those uses and as a prophylactic alternative to nuisance tort law.4 However, local governments quickly used this authority to perpetuate racial and economic segregation and entrench redlining. California’s growth has been shaped by this legacy, as California cities are the sites of the first racial zoning ordinance (in San Francisco 1890),5 the first comprehensive zoning ordinance with single-family only zones (Berkeley in 1916),6 and the first Neighborhood Preservation Ordinance (Berkeley in 1973).7 In California, a city’s land use and zoning authority derive from the city’s police power in the California constitution, as long as it is not in conflict with state laws; thus, regulation can control land use and development standards to serve the public “welfare,” but cannot target specific businesses or groups of people.

Municipal Zoning & General Plans

State of California Planning and Zoning Law (Gov. code sections 65000 - 66035) requires general-law cities to have a long-term (typically twenty-year) comprehensive plan that defines the development of the city, including a Land Use, Circulation, Housing, Conservation, Open Space, Noise, and Safety Element. Residential land use is usually defined in the Land Use and Housing elements; the latter is the mechanism through which the State of California monitors the implementation of state housing goals. Passing a General Plan is a legislative act, and General Plan updates and adoptions can take months to years. General land use plans must be “horizontally consistent” (guidance within elements should be in agreement) and “vertically consistent” (all other ordinances must follow general plan). 

The legal relationship between general plan and zoning has been established through several CA Supreme Court cases (primarily Lesher Communications, Inc. v. City of Walnut Creek, 1990): general plans are charter documents for city ordinances; they should provide a clear vision for the community to shape future ordinances, but be broad enough to be useful for many years. After a general plan is approved, all zoning ordinances passed must be in alignment with the General Plan (typically that check is within the purview of the city council).8 Zoning ordinances that become “inconsistent” with a newly general plan (i.e. a previously zoned single-family residential area is now deemed multi-family in the general plan) are supposed to be amended to match the general plan “within a reasonable time.”9 While there is no standard mechanism for making sure zoning codes are updated, there are several state laws that include consistency requirements through which the general plan / zoning code hierarchy is codified. For example, state affordable housing density bonuses increase maximum allowable residential density when developers are contributing to affordable housing; if the density of the zoning ordinance is inconsistent with the general plan, the general plan density is followed.10

Up until 2019, the major exception to this general plan / zoning code hierarchy mandate is the case of charter cities, whose municipal zoning power comes not from the CA state general laws but their own set of charters. Charter cities generally have more agency within land use decisions, and are not bound to follow state law for “municipal affairs” (of which there is court precedent that zoning falls within). Historically, zoning code did not need to be aligned with the general plan unless the city passed a consistency requirement, except for cities over 2 million residents (Los Angeles).11 SB1333 (passed 2018, enacted January 1, 2019) amended state code (Gov. code section 65803) to apply all consistency requirements to charter cities as well.12 This change applies to all charter cities in California, which include most of the largest cities.13

Zoning is set by municipal ordinance and translates the long-range general plan into near-term local law. The efficacy of the vision and values in a general plan relies largely on the translation into zoning ordinance. Typically, a city council will pass a single, holistic zoning “ordinance” (the zoning code) that defines or updates the full set of municipal zones and their allowable or conditional use, shape, density, etc. A map that defines the boundaries of zones in the community must be passed with the zoning ordinance. The zoning map should generally be consistent with the land use map, but does not have to be identical, as there can be several zoning types that fall into a general plan category.

Those map differences often reflect the differences in timing of zoning code, as compared to the general plan. In many cases, the general plan will inherently require a gradual implementation of zoning code updates, in order for the city to stay consistent with all components of the general plan beyond land use (such as requirements of consistent public services, transportation, etc.). The CA Office of Planning and Research recommends, when possible, that general plan amendments and corollary zoning changes be passed concurrently. When not possible, they suggest a timeframe to update the zoning code of six months for minor general plan changes (small area changes), and two years for extensive amendments (large area changes; full updates). Otherwise, general plans should provide guidance on the timing of future development and corresponding zoning code updates.14

Zoning Code Components

A general plan will typically define broad categories such as neighborhood vision, land use category (i.e. residential), housing type (i.e. rowhomes), and density (i.e. two units per parcel). Zoning ordinances contain many other components whose combination can enable (or limit) development within the intended land use. Brief descriptions of these components are below:15

• Use: What the land will be used for (i.e. commercial, public land, single-family residential, medium-density residential)

• Density: Number of buildings or individual units per ground area. For residential, typically defined as dwelling unit (du) per acre or dwelling unit per lot (i.e. single-family zoning within and across cities may range in du/acre limits, but would always be 1 du/lot)

• FAR: Floor area ratio; the ratio of total building floor area to lot area. A FAR of 2.0 means a building can have up to two times the square feet than exists in the lot (such as a four-floor building with a footprint covering half the lot). This does not regulate how the building will look (height, width) but how much there will be

• Lot size: Lot size limits. Minimum lot sizes are used often in suburban, single-family zones to maintain and ensure a certain amount of lawn / green space, and maintains a barrier to access certain neighborhoods16

• Lot coverage: The portion of the lot that a building footprint covers, regardless of height. (i.e. 30 percent) 

• Setbacks: Minimum distance a structure must be from the property line, creating a uniform building line for a city block. Front, rear and side setbacks typically vary (side setbacks are usually smaller) 

• Building Heights: Vertical height of building, either in feet or stories

• Parking minimums: Number of off-street parking spaces required per building area, building, or unit. Single family residential zoning typically regulates off-street parking as two off-street spots per home; multi-family residential typically defines one parking spot per unit 

• Accessory Use: An additional structure that is not the primary purpose of the lot but enhances it, such as garages or sheds. They typically follow different rules than the primary structure. This category includes Accessory Dwelling Units (ADUs), small housing units that share a lot with another building but are detached and do not change the visual landscape of the neighborhood

The combinations of these components define the true built capacity for an area, and thus several components must be updated in order to enable new land uses to actually be built.17 For example, an increase in residential density to enable fourplexes on previously single-family lots would likely also require an increase in FAR, an increase in allowable lot coverage, paired with decreases in setbacks so that necessary extensions can be made. 

Zoning Reform Process 

There are different pathways to zoning reform of single-family residential zoning and other restrictive zoning categories, but they all require city council approval, integration into the zoning ordinance, and updating the general plan. Cities have taken several different approaches: engaging changes through a general plan update, coordinating policies through a housing task force, or passing resolutions of intent. To cement the reform as long-term change in California, general plan updates seem unavoidable. Even after general plan updates, however, the details of zoning ordinances must be changed to match new land use. Considering zoning reforms that are city-wide, these two planning processes alone could take four to five years to complete.  

The process of zoning reform can be thought of in phases, each with their own timeline: Research, Negotiation, Plan Development, Codification, and Implementation Tracking. The table below outlines a framework of those phases, including what might happen, who is involved, and how long it appears to take. This is a rough schema, and not intended to be universal; cities do not need to engage in all of these policy stages to enact change. 

Types of Zoning Reform

“Upzoning” encompasses any zoning changes that increase the density or increase the utility of a parcel's land use. “Upzoning” for residential development primarily occurs on non-residential urban lots that can be rezoned for multi-family residential or mixed use commercial. Single-family zoning reform refers to a specific type of upzoning that has been historically more challenging: increasing the density of single-family residential to allow for multi-family residential units. Attempts to do this upzoning have been stymied in the past by processes of public input and complaints from single-family homeowners. 

Zoning reform can follow many forms, and there is a wealth of academic proposals of the structure that reform should take. Some zoning structures that cities’ reforms of single-family zones have followed include:

• Form-based code: prescriptive code that describes how the built land form will appear, rather than specific allowances of use. Typically this requires more detailed ranges of zoning components, rather than just max/min values, and allows for a wider range of mixed uses. Example: Minneapolis, MN 

• Incentive zoning: zoning incentives (such as relaxed restrictions, fewer parking requirements) for developers that guide them to certain types of investments (such as public transportation or affordable units). Example: Seattle, WA; Minneapolis, MN 

• “Smart Growth” / Transit Oriented Development (“TOD”): targeted residential upzoning or development incentives within walking distance of transit stations, typically train lines. This changes zoning only within a certain area to encourage residential density in areas that have public transportation access. Example: Seattle, WA 

• Wholesale Density changes: Maintaining typical use-based codes, but raising the densities of single-family residential to allow for multi-units. Example: Sacramento, CA

The tables below outline the phases described above and the staging of current reform efforts. The accompanying spreadsheet (Zoning Reform Tracking Sheet) describes these initiatives in more detail. The Othering and Belonging Institute plans to update this spreadsheet on a periodic basis.