Sonoma, CA Parking Rules: Driveway Rules (2026)

Article 86 of the Sonoma County Zoning Code (Chapter 26) sets off-street parking requirements: Sec. 26-86-010 requires two spaces per single-family dwelling (which may be in a garage, carport, or open paved area), one space per ADU subject to the state-law exemptions in Sec. 26-88-060, two spaces per dwelling unit in multi-family up to four units, and various standards for non-residential uses (e.g., one space per 250 square feet of retail floor area). Parking spaces must be at least 9 feet wide by 18 feet long, with maneuvering aisles sized by Sec. 26-86-020. Garage and carport conversions that eliminate required off-street spaces generally trigger Sec. 26-86-010(F) replacement-parking obligations, though state ADU law (Cal. Gov. Code Sec. 65852.2(d)(11)) prohibits the County from requiring replacement parking when a garage is converted to an ADU. Driveway access onto a county-maintained road requires an encroachment permit issued by Sonoma County Public Infrastructure (formerly Transportation and Public Works) under Chapter 11 of the County Code, which sets standards for driveway width (typically 12 feet minimum for residential, 20 feet for commercial), sight-distance triangles at the road intersection, surfacing (asphalt or approved alternatives), drainage culverts, and apron grade limits. Driveways onto state highways (US 101, SR 1, SR 12, SR 116, SR 121, SR 128) require a Caltrans encroachment permit instead, under Streets and Highways Code Sec. 660 et seq. Driveways serving parcels in CAL FIRE State Responsibility Areas (SRA) or designated Very High Fire Hazard Severity Zones must comply with Public Resources Code Sec. 4290 and Title 14 California Code of Regulations Sec. 1273 (the SRA Fire Safe Regulations adopted by the State Board of Forestry in 1991 and amended in 2022) plus the California Fire Code Chapter 5 as adopted in Sonoma County Code Chapter 13: 20-foot minimum unobstructed driveway width for two-way travel (or 12 feet with mandatory turnouts every 400 feet), 14-foot vertical clearance, all-weather surfacing capable of supporting a 75,000-pound fire-apparatus loaded weight, gradient not exceeding 16% (with limited exceptions to 20%), and a turnaround (hammerhead or cul-de-sac) at the end of any dead-end driveway longer than 150 feet. These standards became particularly important after the 2017 Tubbs Fire investigations highlighted narrow driveways in Mark West Springs and Larkfield-Wikiup that prevented engine access. Driveways shared by multiple parcels often require a recorded private-road maintenance agreement. Parking of vehicles in the front-yard setback on unpaved or non-designated areas (e.g., on the lawn) may violate Article 88 design standards for some residential combining districts and is also addressed by accumulated-nuisance provisions in Chapter 1 of the County Code. Driveway gates must be set back at least 30 feet from the road edge to provide off-road queuing space and must comply with California Fire Code Sec. 503.6 (Knox-box or radio-controlled access for fire apparatus on gated driveways serving more than four parcels).