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

Classification of one's ownership rights in land. One way either buy the land and own all rights to it or lease it where one's rights are described in and limited by the lease agreement. ...

Purchase of part of property or property rights when condemnation takes place. The owner must be justly reimbursed. ...

A method of purchasing real estate whereby a maximum amount of leverage is used. Normally the seller will finance the down payment necessary to acquire a mortgage. Thus, the purchaser is ...

Single-family dwelling attached to other units by common walls. ...

Location Analysis is the appraisal of a general geographic area for a particular use. A Residential Real Estate Market professional (or consumer) rarely deals with a Location Analysis ...

Percentage of royalties derived from an oil and gas lease payable to someone other than the property lessor. It is a net royalty interest in the oil and gas recovered at the surface free of ...

Right of tenant to make use of a property's wood or food producing capacity to provide for his or her own necessities. ...

Contains the appliances necessary for the maintenance of an establishment. ...

Half oval window. It is usually small and placed over a doorway serving a decorative purpose. In some case, the window may be mounted with a hinge at either end to a permit opening for ...

Popular Real Estate Questions