Kirkland, WA Fence Regulations: Retaining Walls (2026)

Kirkland follows the Washington State Building Code and International Residential Code as adopted locally. A building permit is required for any retaining wall exceeding 4 feet in height measured from the bottom of the footing to the top of the wall, and for any wall of any height that supports a surcharge (additional load) such as a driveway, deck, or structure above. Combined fence-and-retaining-wall height in a required yard is capped at 6 feet total if the two elements are within 5 feet of each other under KZC 115.40. Kirkland has significant steep slope terrain on Finn Hill, along the Lake Washington bluff in Moss Bay and Houghton, and around Juanita Creek and Forbes Creek ravines. Walls in critical areas (steep slope, landslide hazard, wetland, or stream buffer) require a Critical Areas Review with geotechnical engineering report regardless of height. Rockeries (stacked rock without mortar) over 4 feet also need permits and engineered design. Drainage must discharge to approved stormwater facilities, not across neighboring property.