Santa Rosa ADU Zoning Rules & Permit Guide

ADU Regulations in Santa Rosa, California

Updated September 29, 2026

Nestled in Sonoma County, Santa Rosa has been proactive about ADUs since the 2017 wildfires, streamlining permit processes as part of the city's recovery and housing resilience strategy. The Urban Growth Boundary may influence lot coverage for larger properties.

Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in Santa Rosa as of 2026. Regulations are governed by California's AB 68 (2020), AB 881 (2021), and AB 3182 (2024) which together establish a statewide ADU framework.

Additional Local Requirements for Santa Rosa

• Height limit: 16-18 ft
• Urban Growth Boundary constraints may apply
• Conversion of existing space encouraged
• Fire sprinklers may be required

Frequently Asked Questions About ADUs in Santa Rosa

Can I build an ADU in Santa Rosa?

Santa Rosa has been proactive about ADUs since the 2017 wildfires, streamlining permit processes to encourage more housing.

What is the maximum ADU size allowed in Santa Rosa?

ADUs in Santa Rosa can be up to 1,200 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the Santa Rosa planning department before designing your project.

What are the setback requirements for an ADU in Santa Rosa?

ADUs in Santa Rosa generally require setbacks of 4 ft rear, 4 ft side. California state law (AB 68) limits local setback requirements to 4 feet for existing structures, but always verify with local zoning.