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

Franklin County's landscaping and screening chapter treats a retaining wall and anything built on top of it as one combined structure for height purposes. Section 17.74.050(B) starts from the general fence rule: height is measured from whichever grade, existing or finished, is lower, and on a sloping lot the height can be averaged in six-foot segments but never exceeds eight feet at any point. The same subsection then addresses the specific case of a fence or hedge placed above a retaining wall used to raise a lot's grade: the retaining wall and the fence or hedge together cannot exceed nine and one-half feet.

The code carves out one exception. If the retaining wall exists to hold back a cut into the grade, rather than to raise it, the normal fence-height limits (four feet in a front yard, six feet in side and rear yards under subsections C and D) apply to the fence alone, not the combined structure, provided the fence is set back at least three feet from the top of the retaining wall. That distinction matters most on sloped lots along the Snake and Columbia river bluffs and in the county's rural residential districts, where property owners commonly terrace a yard rather than build on the natural slope. Enforcement runs through the planning director or code enforcement officer under Section 17.74.110, with the Board of Commissioners authorized under Section 17.74.120 to place a lien on the property if a violation is not corrected after written notice.