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Zoning 101

NYC Zoning Glossary

25-Foot Rule

Applies to an existing zoning lot that is split between two or more zoning districts that permit different uses or have different bulk rules. When the width of the portion of the zoning lot in one of the districts measures 25 feet or less at every point, the use or bulk rules of the larger district can be applied to the entire zoning lot.

As-of-right Development

A development that complies with all applicable zoning regulations and other laws, and does not require any discretionary action by the City Planning Commission (CPC) or Board of Standards and Appeals (BSA). A large majority of development in the city is as-of-right.

Base Flood Elevation

A flood protection standard that is the height that has a one percent chance of being equaled or exceeded by a flood in any given year, as determined and represented on maps generated by the Federal Emergency Management Agency. Space in buildings below the base flood elevation is restricted by the Building Code.

Base Height

The maximum permitted height of the front wall of a building before any required setback.

Building Envelope

A three-dimensional space that defines the maximum volume within which a structure can be built on a zoning lot. This is shaped by applicable height, setback, lot coverage and yard controls.


The combination of controls including lot size, floor area ratio, lot coverage, open space, yards, height and setback that determine the maximum size and placement of a building on a zoning lot.

Commercial Overlay

A C1 or C2 District is mapped within Residence Districts to accommodate local retail and services (grocery stores, dry cleaners, restaurants, for example). These districts, designated by the letters C1-1 through C1-5 and C2-1 through C2-5, appear on the Zoning Map as a pattern superimposed on a Residence District.

Contextual District

A zoning district that regulates the height and bulk of new buildings, their setback from the street line, and their width along the street frontage, to reflect a form consistent with the scale and character of many neighborhoods. Residence and Commercial Districts with an A, B, D or X suffix are contextual zoning districts.


A change of a building’s use to another use category, such as from a commercial to a residential use group.

Corner Lot

A zoning lot that adjoins the point of intersection of two or more streets. A zoning lot bounded entirely by streets is also considered a corner lot.


Generally refers to a combination of bulk and concentration or intensity of use, often describing extent or degree of concentration. For residential use, density is often used descriptively to refer to the dwelling unit factor.

Development Rights

Generally speaking, an amount of floor area permissible on a zoning lot. When the floor area that has been built is less than the maximum amount of floor area permitted, the difference is often referred to as “unused development rights.

Dwelling Unit Factor

A number by which total residential floor area is divided to calculate and regulate the maximum number of dwelling units permitted in a building. The factor varies by zoning district


A special zoning label placed on a property as part of a discretionary action that requires specified environmental issues be addressed before a building is constructed or enlarged or the use of the land changes.


A change to an existing building that increases its floor area, or an expansion of an existing open use onto a portion of a zoning lot not previously used for that purpose

Environmental Impact Statement (EIS)

A detailed study that examines the environmental effects of a project requiring a discretionary action. An EIS is required when a more limited analysis is not sufficient to conclude that the project would not result in significant adverse effects on the environment. e study looks at a variety of environmental categories, typically including traffic, schools, air quality, noise and building shadows


An expansion of an existing use to occupy additional existing floor area within a building.

Flood Zone

The area of the city that is at risk of flooding in an event that has a one percent annual chance of occurring, as designated by the Federal Emergency Management Agency. In a flood zone, special Building Code requirements apply, and special zoning provisions are available to enable compliance with the Building Code and reduce the vulnerability of buildings.

Floor Area Ratio (FAR)

The principal bulk regulation that controls the size of buildings. Each zoning district specifies a maximum FAR for a use which, when multiplied by the lot area of the zoning lot, produces the maximum amount of floor area allowable for that use on that zoning lot.

FRESH Food Store

A grocery store meeting certain requirements in one of the underserved neighborhoods designated under the Food Retail Expansion to Support Health (FRESH) program to increase the availability of fresh, healthy food. FRESH Food Stores are eligible for floor area and financial incentives.

Height Factor

A number equal to the total floor area of the building divided by its lot coverage (in square feet), used to determine floor area limits and lot coverage requirements. In general, the height factor is equal to the number of stories in a building constructed without setbacks. Height factor applies only in R6 through R9 non-contextual districts.

Height Factor Building

A building containing residences whose residential bulk is determined by a corresponding range of height factors, floor area ratios and open space ratios, and is set within a sky exposure plane. Higher floor area ratios are permitted for tall buildings surrounded by open space. Height factor buildings are permitted only in R6 through R9 noncontextual districts

Incentive Zoning

A term often used to refer to additional floor area or other zoning flexibility permitted in exchange for providing a use, public amenity or facility that contributes to planning objectives. Incentive zoning exists in certain areas to promote privately owned public spaces, improvements to nearby subway stations, preservation of a theaters, FRESH food stores, and affordable housing.

Inclusionary Housing Program

Zoning provisions established to create and preserve housing that is affordable to low- and moderate-income households to promote neighborhood economic diversity. There are three branches of the Inclusionary Housing programs, including voluntary, incentive-based programs and the Mandatory Inclusionary Housing program. Each branch of the program has specific standards and applicability.

Initial Setback Distance

A setback requirement for buildings using the sky exposure plane regulations available in non-contextual districts.

Large Scale Development

A development generally involving several zoning lots that are planned together as a unit. The large-scale development regulations allow modifications to various zoning regulations. Such modifications can allow for design flexibility to achieve a better site plan. Large-scale developments require a discretionary action from the CPC.

Limited Height District

A zoning designation established prior to the creation of contextual districts, superimposed on certain areas designated as historic districts by the Landmarks Preservation Commission (LPC). Limited Height Districts cap total building heights and are mapped in areas of the Upper East Side, Gramercy Park, Brooklyn Heights and Cobble Hill.

Lower Density Growth Management Area (LDGMA)

An area designated in the Zoning Resolution in which developments must provide more accessory parking, larger yards and more open space than would otherwise be required in the same zoning districts elsewhere. LDGMAs exist in Staten Island and Community District 10 in the Bronx.

Mandatory Inclusionary Housing (MIH)

A zoning provision that requires a share of new housing in areas rezoned for higher residential density to be permanently affordable to low- and moderate-income households. The required amount of affordable housing and income levels vary based on several options specified in the Zoning Resolution.

Manufacturing District

Designated by the letter M (M1-1, M2-2, for example), Manufacturing Districts are zoning districts in which manufacturing uses, most commercial uses and some community facility uses are permitted. The manufacturing uses are subject to a range of performance standards. New residential development is not allowed, except under certain conditions in M districts with a “D” suffix, or in Mixed Use Districts.

Mixed Use District

A Special Purpose District mapped in numerous locations within the city that includes allows a wide range of uses, based on the regulations of an M1 district and a Residence District. The M and R districts are mapped together (M1-2/R6, for example) as paired districts and designated by the prefix “MX” on the Zoning Maps. New residential and non-residential uses are permitted within the same building, with certain restrictions, and any such building is a mixed building.

Open Space

The part of a zoning lot containing residences that is open and unobstructed from its lowest level to the sky, except for specific permitted obstructions, and is accessible to all residents. Open space may include courts or yards.

Open Space Ratio

A number specified in the Zoning Resolution that is used to calculate the amount of open space required on a zoning lot containing residences in R6 through R10 noncontextual districts, expressed as a percentage of the total floor area on the zoning lot. For example, if a building has 20,000 sf of floor area has a required OSR of 20, then 4,000 sf of open space would be required on the zoning lot (0.20 x 20,000 sf).

Overlay District

A zoning district superimposed upon another that supersedes, modifies or supplements the underlying district’s regulations. Commercial overlay districts and Limited Height Districts are examples.

Paired Districts

These match an M1 District with an R3 through R10 district (M1-5/R10, for example) to permit a mixture of residential and non-residential uses (commercial, community facility, light manufacturing) in the same zoning district, block or building. Paired districts are often mapped in Mixed Use Districts.

Predominantly Built-Up Area

A blockfront that is entirely within an R4 or R5 Residence District (without a suffix) in which optional regulations that permit higher FAR and lower accessory parking requirements may be used to produce infill housing.

Qualifying Ground Floor

A ground floor of a development or enlargement of a Quality Housing building, where the second story begins 13 feet or more above the level of the sidewalk and, in certain instances, where additional supplementary use provisions are met. In some zoning districts, buildings with a qualifying ground floor are permitted a higher maximum base height and overall height.

Quality Housing Program

The program, mandatory in contextual R6 through R10 Residence Districts and optional in non-contextual R6 through R10 districts, encourages development consistent with the character of many established neighborhoods. Its bulk regulations set height limits and allow high lot coverage buildings that are set at or near the street line. The Quality Housing Program also requires amenities relating to interior space, recreation areas and landscaping.

R10 Districts Outside Inclusionary Housing Areas

R10 districts permit the highest residential density in the city. This high density can also be achieved in commercial districts that permit an R10 residential district equivalent.

Residence District

A zoning district, designated by the letter R (R3-2, R5, R10A, for example), in which only residences and community facilities are permitted.

Residential District Equivalent

A zoning designation assigned to a C1, C2, C3, C4, C5 or C6 District that establishes the regulations for any residential uses within the district, usually referred to as a “residential equivalent.” For example, the residential portion of a building in a C4-4 District must follow the bulk regulations of its residential equivalent, an R7 District.

Rezoning or Remapping, or Zoning Map Amendment

Common terms used to describe when the zoning designation for an area is changed on the Zoning Map, as a result of an application from a private or public entity. is action is subject to Uniform Land Use Review Procedure.

Rezoning- SoHo-NoHo

Common terms used to describe when the zoning designation for an area is changed on the Zoning Map, as a result of an application from a private or public entity. This action is subject to Uniform Land Use Review Procedure.

Semi-detached Building

A building that shares a wall, on a side lot line, with another building on an adjoining zoning lot, and the remaining sides of which are surrounded by open areas or street lines.

Setback, Building

A requirement for the upper floors of a building to be located further from a lot line than lower floors to allow more light and air to the street or the lower stories of the building.

Silver Building

A tall building or enlargement that is 45 wide or less, in an R7-2, R7X,R8, R9 or R10 district, is commonly called silver building. Such buildings are generally restricted to a height equal to the width of the abutting street or 100 feet, whichever is less.

Sky Exposure Plane

A plane that defines the building envelope in non-contextual districts designed to protect light and air at street level. e sky exposure plane is a virtual sloping plane that begins at a specified height above the street line and rises inward over the zoning lot at a ratio of vertical distance to horizontal distance set forth in district regulations

Sliver Rule

A common term for restrictions that apply to a building or enlargement that is 45 feet wide or less, in many medium and high density Residence Districts. Such buildings are generally limited to a height equal to the width of the adjacent street or 100 feet, whichever is less.

Special Permit

A discretionary action by the City Planning Commission (CPC), or the Board of Standards and Appeals (BSA), that allows modification of zoning regulations if certain conditions and findings specified in the Zoning Resolution are met

Split Lot

A zoning lot located in two or more zoning districts and divided by a zoning district boundary. In most cases, zoning regulations for each district must be applied separately for each portion of the lot. Special rules exist for zoning lots that existed prior to 1961, or prior to any rezoning that split the lot.

Transfer of Development Rights

In limited circumstances specified in the Zoning Resolution, TDR allows for the transfer of unused development rights from one zoning lot to another, to preserve historic buildings, open spaces or unique cultural resources. For such purposes, TDR may be permitted where the transfer could not be accomplished through a zoning lot merger. In the case of a landmarked building, for example, a transfer may be made by CPC special permit to a broader area than permitted through a zoning lot merger.

Zoning District

A specifically delineated area of the city within which various combinations of the zoning regulations govern land use, building bulk, parking and streetscape. Zoning districts include Residence Districts, Commercial Districts, and Manufacturing Districts, and are shown on the Zoning Maps.

Zoning Lot Merger

The joining of two or more adjacent zoning lots into a single new zoning lot. As part of the merger, unused development rights may be located anywhere on the new lot, as-of-right, as long as the entire merged lot complies with all applicable provisions of the Zoning Resolution.