Fairfield, CA Fence Regulations: Retaining Walls (2026)

Solano County Building & Safety Services lists retaining walls that are not over 4 feet in height - measured from the bottom of the footing to the top of the wall - among the structures exempt from a building permit. That exemption does not apply when the wall supports a surcharge (an added load such as a building, slope, or driveway above it) or impounds liquids; those walls require a building permit and engineering regardless of height. Because the 4-foot measurement starts at the bottom of the footing, a wall that appears under 4 feet above grade can still exceed the threshold once the footing depth is counted. Retaining walls must also satisfy Chapter 28 zoning placement rules and may affect drainage onto neighboring property. A retaining wall combined with a fence on top is evaluated for both the wall permit thresholds and the fence height limits in Section 28.93.A.3. For walls near or on a property line, owners should confirm the boundary and any easements, and walls within a road right-of-way require Public Works review.