ADU Regulations in San Bruno, California (2026)

Regulations at a glance

Local rules & notes

60-Day Deemed Approved Rule: If the city fails to approve or deny a completed ADU application within 60 days, it is legally deemed approved. Unpermitted Unit Amnesty: The city cannot deny a permit for an unpermitted ADU built before 2020 based on building code violations unless they are health and safety issues. HOA Interference Prohibition: Homeowners associations and third parties are strictly prohibited from influencing or blocking ADU approvals.

For the official ordinance and latest updates, check your city or county planning department.

Frequently asked questions about ADU regulations in San Bruno

• What is the maximum ADU size in San Bruno, California?

  In San Bruno, the maximum ADU size is typically 1200 square feet, depending on whether the unit is attached or detached. California state law allows up to 1,200 sq ft for detached ADUs and 800 sq ft for attached in many jurisdictions; San Bruno may follow state defaults or have local limits. Verify with San Bruno planning for your specific lot.

• What are the setback requirements for ADUs in San Bruno?

  In San Bruno, typical setback requirements are 4 feet from the side property line and 4 feet from the rear. These may be reduced to 4 feet under California Government Code § 65852.2 where applicable. Check with San Bruno planning for overlay zones or design standards that could affect your site.

• What is the maximum height for an ADU in San Bruno?

  In San Bruno, the maximum height for an ADU is generally 16 feet. State law often allows up to 16 feet for detached ADUs and up to 25 feet when within 4 feet of the property line in some cases. Confirm with San Bruno or county planning for your zone.

• Is ADU approval ministerial in San Bruno?

  In San Bruno, ADU approval is typically Ministerial (by-right) per Gov Code §65852.2. Ministerial (by-right) review means the city must approve qualifying applications without discretionary review, per California Gov Code § 65852.2. Your project must still meet objective standards; San Bruno planning can confirm the exact process.

• Are there parking requirements for ADUs in San Bruno?

  In San Bruno, parking for ADUs is generally false. California law often waives parking for ADUs within a half-mile of transit or in certain historic districts. Check with San Bruno planning for your address.