Zoning is a term used in urban planning for a system of land-use regulation in various parts of the world, including North America, the United Kingdom, and Australia. The word is derived from the practice of designating permitted uses of land based on mapped zones which separate one set of land uses from another. Zoning may be use-based (regulating the uses to which land may be put), or it may regulate building height, lot coverage, and similar characteristics, or some combination of these.

Scope

Theoretically, the primary purpose of zoning is to segregate uses that are thought to be incompatible; in practice, zoning is used as a permitting system to prevent new development from harming existing residents or businesses and to preserve the "character" of a community. Zoning is commonly controlled by local governments such as counties or municipalities, though the nature of the zoning regime may be determined or limited by state or national planning authorities or through enabling legislation. In Australia, land under the control of the Commonwealth (federal) government is not subject to state planning controls. The United States and other federal countries are similar.

Zoning may include regulation of the kinds of activities which will be acceptable on particular lots (such as open space, residential, agricultural, commercial or industrial), the densities at which those activities can be performed (from low-density housing such as single family homes to high-density such as high-rise apartment buildings), the height of buildings, the amount of space structures may occupy, the location of a building on the lot (setbacks), the proportions of the types of space on a lot (for example, how much landscaped space and how much paved space), and how much parking must be provided. The details of how individual planning systems incorporate zoning into their regulatory regimes varies though the intention is always similar. For example, in the state of Victoria, Australia, land use zones are combined with a system of planning scheme overlays to account for the multiplicity of factors that impact on desirable urban outcomes in any location.

Most zoning systems have a procedure for granting variances (exceptions to the zoning rules), usually because of some perceived hardship caused by the particular nature of the property in question.

Types of residential zones would be R1 for single-family homes, R2 for two-family homes, and R3 for multiple-family homes.

Types

Zoning codes have evolved over the years as urban planning theory has changed, legal constraints have fluctuated, and political priorities have shifted. The various approaches to zoning can be divided into four broad categories: Euclidean, Performance, Incentive, and Design-based.

Euclidean

Named for the type of zoning code adopted in the town of Euclid, Ohio, and approved in a landmark decision of the U.S. Supreme Court, Euclidean zoning codes are by far the most prevalent in the United States,Fact: date=June 2007 used extensively in small towns and large cities alike. Also known as "Building Block" zoning, Euclidean zoning is characterized by the segregation of land uses into specified geographic districts and dimensional standards stipulating limitations on the magnitude of development activity that is allowed to take place on lots within each type of district. Typical types of land-use districts in Euclidean zoning are: residential (single-family), residential (multi-family), commercial, and industrial. Uses within each district are usually heavily prescribed to exclude other types of uses (residential districts typically disallow commercial or industrial uses). Some "accessory" or "conditional" uses may be allowed in order to accommodate the needs of the primary uses. Dimensional standards apply to any structures built on lots within each zoning district, and typically take the form of setbacks, height limits, minimum lot sizes, lot coverage limits, and other limitations on the "building envelope".