ADU Regulations in Palo Alto, California (2026)

Regulations at a glance

Local rules & notes

Illegal Tree Ordinance Delays: The city attempted to use its Tree and Landscape Preservation regulations (Chapter 8.10) to delay or deny ADU permits, which is prohibited by state law. Local Historic Inventory Overreach: Palo Alto applies restrictive ADU standards to its local historic inventory; however, state law only allows such restrictions for properties on the California Register of Historical Resources. Prescriptive JADU Kitchen Requirements: The city mandates specific appliance sizes (e.g., 10 cubic foot refrigerator) and counter dimensions for JADUs, which exceeds state 'efficiency kitchen' standards.

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

Frequently asked questions about ADU regulations in Palo Alto

• What is the maximum ADU size in Palo Alto, California?

  In Palo Alto, the maximum ADU size is typically 800 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; Palo Alto may follow state defaults or have local limits. Verify with Palo Alto planning for your specific lot.

• What are the setback requirements for ADUs in Palo Alto?

  In Palo Alto, 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 Palo Alto planning for overlay zones or design standards that could affect your site.

• What is the maximum height for an ADU in Palo Alto?

  In Palo Alto, 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 Palo Alto or county planning for your zone.

• Is ADU approval ministerial in Palo Alto?

  In Palo Alto, 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; Palo Alto planning can confirm the exact process.

• Are there parking requirements for ADUs in Palo Alto?

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