Brentwood, CA Building Setbacks & Zoning: Setback Rules (2026)

Corner lots present unique setback and visibility requirements. Brentwood's zoning code treats both street-adjacent yards as 'front yards' for setback purposes, meaning a standard R-1 corner lot has a 20-foot setback from each street frontage rather than one 20-foot front and one 5-foot side. The 'interior side yard' (the side abutting a neighbor, not a street) remains subject to the standard 5-foot side setback, and the rear yard follows normal R-1 standards. Fence heights along street-facing corner frontages are limited to 3.5 to 4 feet within the front-yard portion to maintain sight lines. A 'sight visibility triangle' at the corner — typically 25 feet along each curbline — must be kept clear of fences, hedges, trees, and parked vehicles taller than approximately 3 feet. This protects drivers' and pedestrians' line of sight at intersections. Accessory structures, pools, and patio covers generally must meet the street-side setback rather than the interior side-yard setback, which can significantly limit rear-yard use on corner lots. Corner lot owners should carefully review site plans with Planning before building, because violations of the sight triangle are frequent subjects of code enforcement complaints, and fences exceeding the 3.5- to 4-foot limit along the exterior side street require variances or must be set back further.