Spokane County, WA Fence Regulations: Retaining Walls (2026)

Under SCC 3.10.020(d), no person can do any grading without first obtaining a grading permit from the building official. A separate permit is required for each site, and one permit can cover both excavations and fills. Item (2) of the exempted-work list carves out an excavation below finished grade for basements and footings of a building, retaining wall or other structure authorized by a valid building permit. The exemption is narrow. It does not cover any fill made with the material from the excavation, and it does not cover any excavation having an unsupported height greater than five feet after the structure is complete. The subsection closes by stating that an exemption does not authorize work done in violation of the chapter or any other law or ordinance of the jurisdiction.

Two other exemptions in the same list matter for wall projects. Item (8) exempts an excavation that is less than two feet in depth, or that does not create a cut slope greater than five feet in height and steeper than one unit vertical in one and one half units horizontal. Item (1) exempts grading in an isolated, self-contained area when the building official approves it and there is no danger to private or public property.

Where a wall sits at the edge of graded ground, subsection (l) controls the setbacks. The toe of a fill slope must be no nearer the site boundary than one half the height of the slope, with a minimum of two feet and a maximum of twenty feet. The top of a cut slope must be no nearer than one fifth of the vertical height of cut, with a minimum of two feet and a maximum of ten feet. When a fill slope is near the boundary and the adjacent property is developed, the building official can require precautions, and the code lists provision for retaining or slough walls among them. Under subsection (h), fees are charged at the rate in the department fee schedules, and separate plan review fees apply to retaining walls.

SCC 9.75.510 sets a stricter track for walls within county right-of-way or maintained by Spokane County. Analysis and design must conform to the current edition of the AASHTO Standard Specifications for Highway Bridges, and plans and structural computations go to the county engineer/public works director for approval before construction begins. Mortarless concrete block walls must be designed and built to NCMA Technical Report 127. The section carries a Res. No. 16-0288 amendment dated 4-19-2016, and SCC 3.10.020 carries Res. No. 10-1027 dated 11-30-2010.