Zoning in the United States

Zoning is the process of dividing a particular area of land into different districts or zones and specifying certain uses (i.e. residential, commercial, industrial) which can be permitted or prohibited for each. Zoning is carried out by the relevant municipality or county, and is primarily done to segregate uses that are considered to be incompatible, as well as to guide urban growth and development.

Zoning ordinance is a regulation that defines how buildings are to be used in specific zones and, in practice, is set as a means of preventing new development from having a negative impact upon residents and businesses that are already present in the area.

In addition to specifying land use, zoning ordinances may set out site sizes, locations or placements, densities of development, heights of structures, the amount of open space, procedures for handling infractions and granting variances, and so on. If a zone is to be limited to residential use, for example, the zoning ordinance may specify the limitations to be put in place on traffic and noise pollution. Similarly, an area which has a lot of historic buildings and green space may benefit from limiting the height of new buildings to avoid ‘crowding’ the area and help preserve the aesthetic.

Zoning is generally divided into the following categories:

• Euclidean: The most common in the US, this is characterised by the division of land uses into specified geographic districts.
• Performance: This is seen as being less arbitrary and more flexible than Euclidean, and uses performance-based criteria to help developers achieve compliance (e.g. building affordable housing, mitigating environmental impacts, providing public amenities, and so on).
• Incentive: This is a very flexible but complex process whereby a base level of development limitations (e.g. floor-area ratio) is set out and developers adopt them at their own discretion. A reward scale applied to the limitations provides an incentive for developers to incorporate the criteria.
• Form-based: This is a less common approach which involves rules being applied to development sites according to both prescriptive and discretionary criteria.

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[edit] Related articles on Designing Buildings Wiki

• Building codes.
• Building official.
• Change of use class.
• Dominant estate.
• International Building Code (IBC).
• International Zoning Code (IZC).
• Permitted development.
• Planning enforcement.
• Planning permission.
• Servient estate.
• Setback.
• Stop work order.
• Use class designation for land and buildings.