Open Space

In addition to the model ordinance, this section includes other information you may find useful in drafting an open space development ordinance:

Zoning Ordinance from Calvert County, MD: An example of a mandatory open space ordinance, in the Rural District.

Land Preservation District Model Zoning from Montgomery County, PA: This ordinance would also require the preservation of open space certain districts.

Open Space Ordinance from Hamburg Township, MI:  This ordinance incorporates commercial land uses (e.g., mixed use) for projects of a certain size, and provides an example of the application procedure for one community.

Open Space Development is an alternative site planning technique that concentrates dwelling units in a compact area to reserve undeveloped space elsewhere on the site. In this technique, lot sizes, setbacks, and frontage distances are minimized to allow for open space. Also called "cluster development," the typical open space development creates 10-50% less impervious cover and reduces the need to clear and grade 35-60% of the site. Resulting open space areas are often used for neighborhood recreation, stormwater management facilities, or conservation purposes. Open space preserved in a natural condition needs little maintenance and helps to reduce and sometimes treat stormwater runoff from the development. The advantages of open space development include:

  • Reduced impervious cover in a development.

  • Reduced pollutant loads to streams and other water resources.

  • Reduced potential pressure to encroach on resource buffer areas.

  • Reduced soil erosion potential by reducing the amount of clearing and grading on the site.

  • Preservation of green space.

  • Preservation open space for recreation.

  • Lower capital cost of development.

  • Lower stormwater management costs by concentration of runoff in one area and reducing runoff volumes.

  • A wider range of feasible sites to locate stormwater BMPs.

  • Lower costs of future public services needed by the development.

  • Possible increase in property values

  • Creation of urban wildlife habitat "islands."

  • Support other community planning goals, such as pedestrian movement, neighborhood enhancement, farmland preservation, affordable housing, and architectural diversity.

The Model Open Space Ordinance contains language that fosters development that is substantially consistent with local zoning standards, yet allows for modifications from the original standards to insure appropriate, fair, and consistent decision making. The model ordinance sets guidelines for management of open space and the amount of open space required on a site, but is not intended to be a "one-size-fits-all" document.

Stop!Where you see this symbol, you'll need to make a decision or get more information in order to apply this ordinance to your community.


Certain issues have not been covered in this ordinance because many localities provide for them in other ordinances or they are too specific to each community. For example, language on road widths is not included because it is often designated in subdivision or other ordinances. While most ordinances contain a section on the development review process, such language was not included because the review process varies widely by locality.

Reduction of impervious cover is key element in any open space ordinance. There are several ways an open space ordinance can reduce impervious cover. One choice is to set aside a portion of the open space in a natural condition. Impervious cover can be minimized in the recreation area by encouraging the creation of unpaved walkways and/or the use of pervious pavement. Impervious cover can also be reduced by requiring narrower streets, single or no street-side sidewalks, smaller setbacks, and shared driveways. Another key feature of a good open space ordinance is a section outlining reliable methods for open space management. The three primary options are to create a community association or to shift the responsibility to a land trust or the local government, by means of a conservation easement.

Although open space development is desirable, there are challenges to applying open space development criteria in every community. In order for open space development to be successful, the ordinance needs to be crafted in a way that fosters development that is both marketable and environmentally sensitive. The ordinance needs to effectively address issues such as maintenance, liability, and emergency vehicle access. In addition, the community needs to be prepared to manage or dedicate open space to a responsible organization. Finally, decisions about when and where open space development is desired need to be made early on.