Santa Clara County, CA Accessory Structures: Garage Conversions (2026)

Converting an attached or detached garage into an ADU is a ministerial approval in Santa Clara County under California Government Code 65852.2. Replacement parking is not required when a garage is converted to an ADU, overriding any local parking requirement. The conversion requires a building permit to address several code issues: ceiling height must be at least 7 feet (lower for sleeping areas in some conditions), at least one egress window in each bedroom (5.7 sq ft openable area), a second exit door, insulation meeting Title 24 energy code, electrical service sized for the new load, smoke and carbon monoxide alarms throughout, and fire separation walls if attached to the main home. Plumbing is typically added for a kitchen and bathroom. A dedicated heating source is required; heat pumps are a common and code-friendly option. Conversions in Very High Fire Hazard Severity Zones must address ember-resistant vents and exterior materials. Garages converted to non-ADU living space (extra family room) follow similar building code standards but may trigger additional zoning review.