Definition of "Open space ratio"

Gena Taylor real estate agent

Written by

Gena Taylorelite badge icon

Coldwell Banker FI Grey & Son Residential Inc.

When talking about the open space ratio we are referring to a term that is used in zoning laws and regulations. The open space ratio is a term used to measure open space on a developed land or zoning lot. The open space ratio is calculated in the percentage of open space in the building's square footage. For example, a housing subdivision containing 100 acres has devoted 10 acres to open space. Therefore, the open space ratio is 1/10 or 10 percent (10/100). Or an office building of 10,000 square feet with an open space ratio of 20% will have 2,000 square feet designated to remain open space.

Open Space Ratio in Residential Real Estate

The term open space ratio is a concept that applies to residential developments, and it usually refers to commonly used open space. While not necessarily a way to determine the ratio of “green” open space on lots of land proposed for residential development. The term open space ratio can refer to two types of open space:

  • Allowable Areas

Allowable open space are the areas that are required common areas to be maintained and remain undeveloped for the benefit of those living or working on the lot parcel: parking lots, yard requirements, floodplains, recreational areas, stormwater management systems, etc.

  • Prohibited Areas

Prohibited open space areas are privately owned sites that are not accessible for those living or working on the lot parcel and that are also available for further structural developments.

How is Open Space Ratio Calculated?

The open space ratio is a zoning law used by municipalities to be able to control the types of buildings built, their height, and their ratio of open space. It is a means for municipalities to ensure that the open space available on a developed land makes up a certain percentage of the lot developed. In most cases, that requirement is of a 20% open space ratio.

Open Space Ratio Formula:

Open Space Ratio (OSR) = Commonly-owned Open Space / Total Area Proposed for Development


So if you have 12 acres available for residential development and you have 6 acres of commonly-owned open space (ponds, recreation area, parking area, buffers, etc) you will have an open space ratio of 50%.

image of a real estate dictionary page

Have a question or comment?

We're here to help.

*** Your email address will remain confidential.
 

 

Popular Real Estate Terms

A gift by will of real property. Absolute legasy: An unconditional and immediate gift. Conditional legasy: The bequest of a gift depends on the occurrence of something happening. For ...

A caveat vendor is a legal principle where the seller is legally responsible for warranting the quality and suitability to task of the item purchased. ...

When a property owner defaults on his or her tax payments, the taxing jurisdiction may force a liquidation of the property or tax sale for the purpose of collecting the owed real estate ...

Supports a structure. ...

Interest rate on a mortgage is changed periodically based on the change in a general price index to take into account inflation, such as a yearly adjustment. An example is the consumer ...

A financial obligation comes in several ways. In general terms, the meaning of liability refers to the amount of money an individual or company owes to a lender. We define the party holding ...

(1) Distribution channel through which originating mortgage lenders distribute mortgages to the Secondary Mortgage Market. Those purchasing mortgages distributed through the conduit ...

Method of constructing a brick, block, or stone wall using mortar in various overlapping patterns. The brick pattern is extremely important in terms of adding strength and stability to the ...

The two terms used to describe professionals in the real estate industry are “realtor” and “real estate agent”. These two terms are used interchangeably or as ...

Popular Real Estate Questions