Sonoma, CA Fence Regulations: Retaining Walls (2026)

Sonoma Municipal Code § 19.46.040, Height limitations for retaining walls (current through Ordinance 13-2025, December 3, 2025), caps retaining walls in the City of Sonoma at 6 feet measured from the finished grade at the base of the wall, with the city planner authorized to approve up to 1 additional foot in consideration of varying topographical features. What sits on top of a retaining wall is governed separately: where a retaining wall protects a cut below finished grade and sits on a front, side, or rear property line, § 19.46.040(B)(1) allows it to be topped by a fence or wall of the same height that would otherwise be allowed on that property line if no retaining wall existed.

Where a retaining wall instead contains a fill, § 19.46.040(B)(2) counts the retaining wall's own height toward the allowable height of any fence or wall built on top of it, so the two heights are added together against the district's normal fence-height cap. Regardless of the retaining wall's height, § 19.46.040(B)(3) always allows an open-work, non-view-obscuring safety fence at the top of a retaining wall, capped at 42 inches. Setback treatment is addressed in § 19.46.040(C): where a wall or fence sits in a required setback area next to a fill-type retaining wall under SMC 19.40.110, the wall or fence must be set back from the retaining wall one foot for every one foot of height, and the strip between the two must be landscaped and kept in good condition. Retaining walls are excluded from the standard fence-height table in SMC 19.46.030, which expressly defers to this section for retaining walls.