Zoning in The United States - Scope

Scope

Theoretically, the primary purpose of zoning is to segregate uses that are thought to be incompatible. However, in practice zoning is used as a permitting system to prevent new development from harming existing residents or businesses. Zoning is commonly exercised by local governments such as counties or municipalities, though the state determines the nature of the zoning scheme with a zoning enabling law. Federal lands are not subject to state planning controls.

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. Some commercial zones specify what types of products may be sold by particular stores. The details of how individual planning systems incorporate zoning into their regulatory regimes varies though the intention is always similar.

Most zoning systems have a procedure for granting variances (exceptions to the zoning rules), usually because of some perceived hardship due to the particular nature of the property in question. If the variance is not warranted, then it may cause an allegation of spot zoning to arise. Most state's zoning enabling laws prohibit local zoning authorities from engaging in any spot zoning because it would undermine the purpose of a zoning scheme.

Zoning codes vary by jurisdiction. As one example, residential zones might be coded as R1 for single-family homes, R2 for two-family homes, and R3 for multiple-family homes. As another example, R60 might represent a minimum lot of 60,000 sq ft (1.4 acre or about 0.5 hectares) per single family home, while R30 would require lots of only half that size.