Usable yard is defined as "one or more well-drained open areas covered with lawn grass or other suitable cover material located on the same lot as the principal use for use by the residents thereon for outdoor activities." Multiple-family dwellings with three or more dwelling units need to provide usable yard under the zoning district regulations.
AMC 21.45.120.I contains additional requirements: "No dimension of a usable yard shall be less than ten feet. A usable yard does not include driveways, common walks, refuse storage or collection areas, or off-street parking or loading areas. However, private balconies or decks containing no less than one ten-foot dimension and roofs available for outdoor activity may be used to meet this requirement. Those balconies or decks with dimensions less than ten feet and containing at least a minimum of 20 square feet may only be counted for up to 50 percent of the required usable yard area.”