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SubjectsPlanning › Zero Lot Line Development
Updated 10/2013

Zero Lot Line Development

Zero lot line development involves the placement of a house on a lot so that one wall is on the property boundary. It is a technique that is used in small lot housing developments to preserve some of the privacy and yard space that is characteristic of single-family dwellings and to enhance their aesthetic appeal. The use of conventional zoning provisions which require that the home must be set back from every lot line is not always practical for small lots since the "yards" created on each side of the house are generally very small. Typically, zero lot line houses are sited on the same one side lot line. Placing the house on one of the side lot lines doubles the amount of usable space on the other side.

Some jurisdictions also include townhouse or condominium development as zero lot line development where the lot line falls between the units that are for sale. In this case, both sides of the unit fall on the lot lines. Other variations on the original zero lot line concept include:

  • Angled Z-lot - Turns the home at a 45-degree angle to the street, which enhances visual appeal and makes it possible to add more windows without compromising privacy.
  • Zipper lot - Varies the depths of rear lot lines; this concentrates open space on one side of the lot, making wider lots possible with only garages located on the property line.
  • Alternate width lots.

Zero Lot Line Code Examples

The following are examples of zero lot line code provisions from Washington cities and counties.

Washington Cities

Washington Counties

General Information on Zero Lot Line Development

This section includes general information on zero lot line development, examples from other states, and illustrations.

  • Portland, OR Zoning Code Ch. 33.110 - Alternative Development Options (Scroll to Section 33.110.240(I))
  • Puget Sound Regional Council, Tool - Zero Lot Line Development - Background information and illustrations
  • Coos Bay, OR Municipal Code Sec. 17.150.020 (includes illustration)

Need more information?

Feel free to Ask MRSC. Washington cities, counties, and our contract partners can call or email MRSC for more information and advice - free of charge.