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

Two or more authorized brokers who agree to cooperate together representing a principal for the completion of a real property sale. ...

Securing lease commitments to a building prior to its being available for occupancy. For example, a developer offers a discounted lease to potential tenants providing they agree to sign a ...

Reduction in taxes payable to the IRS or local government. A tax credit is more beneficial to the taxpayer than an itemized deduction because it reduces taxes on a dollar-for-dollar basis. ...

Mortgage guaranteed up to 30 years by the Veterans Administration to veterans meeting minimum requirements. Originally established by the Servicemen's Readjustment Act of 1944, amended ...

Simply put, the meaning of purchase money mortgage is a type of seller financing. Explicitly, a home seller issues a mortgage to the borrower as part of the buying transaction without ...

Raising money by mortgages and borrowing the money directly from financial institutions. The presence of debt financing provides financial leverage, which tends to magnify the effects of ...

A lien on the property of a mortgagor. In most states a mortgage gives the mortgagee a lien-as opposed to the common-law practice of granting conditional title-on the house or property as ...

Combination of insurance policies on property with each providing an additional increment of coverage exceeding the limits of the preceding policy. For example, policy A adds $70,000, then ...

A reassessment or a reappraising is a decision or strategy made by the owner or the state or local authorities. The reassessment definition is a revision of an earlier assessment. Property ...

Popular Real Estate Questions