Olympia, WA Fence Regulations: Retaining Walls (2026)

Retaining walls in required yards in the City of Olympia fall under the Site Perimeter Grading rule, OMC 18.40.060(C)(6). Within required yard areas, no single retaining wall, and no combination of walls within five horizontal feet of each other, can exceed a height of 30 inches measured from the lowest adjacent grade. The rule also limits the grade itself: no modification of grades or combination of retaining walls can result in grade changes exceeding 30 inches within five feet of a property line, nor 60 inches within 10 feet of an existing or proposed property line. Stacking two short walls does not escape the rule, because walls within five horizontal feet are measured as a combination.

The subsection sits under the fence rule, which defines fences to include walls, and the front yard for these purposes is the first 10 feet of a lot abutting a public street, excluding alleys. Subsection (C)(7) lets the Department approve an administrative exception to maximum fence height and other provisions of these standards when all five conditions exist, and the application must show proposed grades in relation to existing grades.

Downtown Olympia adds its own wall rules. OMC 18.120.370(B)(1)(e) says that where a retaining wall adjacent to a public sidewalk is necessary, the top of the wall surface closest to the sidewalk can be no more than 30 inches high, and taller grade changes use terraces no more than 30 inches high with at least 18 inches horizontal steps between risers.

A separate rule, OMC 12.24.030, requires an owner of premises fronting a public street and below its grade to erect a suitable barricade on the inner line of the sidewalk within five days after notice from the public works director, at the expense of the owner.