Petaluma, CA Fence Regulations: Retaining Walls (2026)

050 of the Implementing Zoning Ordinance treats tall retained embankments as a stepped design problem, not a single wall: once the embankment being retained exceeds 48 inches in height, it must be broken into steps so that no individual exposed retaining wall face is taller than 36 inches, and each intervening step has to be at least 36 inches wide. That keeps a hillside lot from presenting one tall unbroken concrete or masonry face to a neighboring property or the street. Where a retaining wall sits in a required front setback, the ordinance layers on tighter limits: the wall cannot exceed 3 feet 6 inches in height, and it cannot cover more than 5% of the total area of the required front setback, so it stays a modest grade-transition feature rather than a structure that eats the yard.

1, so a stepped retaining wall cannot block a driver's view at an intersection. 060 requires a fence permit from the Community Development Department before any wall is installed or constructed, reviewed against a plot plan and dimensional detail showing materials and height from existing and finished grade. A retaining wall that is also regulated as a structure under Petaluma's state-adopted building code (Municipal Code Title 17) is subject to those separate structural and building-permit requirements in addition to this zoning height and setback limit.