ADU Regulations in Larkspur, California (2026)

Regulations at a glance

Local rules & notes

Illegal Size Cap via Lot Coverage: The city restricts lot coverage increases to 800 sq ft, effectively capping all ADUs at 800 sq ft. HCD states this violates Gov Code 66321 which guarantees larger minimums. Deed Restriction Timing Violation: The ordinance requires a deed restriction be recorded *prior* to building permit issuance. HCD rules this an illegal delay tactic. Denial Procedure Deficiency: The city ordinance allows for simple denial within 60 days. HCD requires the city to provide a full list of defects and remedies upon denial.

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

Frequently asked questions about ADU regulations in Larkspur

• What is the maximum ADU size in Larkspur, California?

  In Larkspur, 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; Larkspur may follow state defaults or have local limits. Verify with Larkspur planning for your specific lot.

• What are the setback requirements for ADUs in Larkspur?

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

• What is the maximum height for an ADU in Larkspur?

  In Larkspur, 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 Larkspur or county planning for your zone.

• Is ADU approval ministerial in Larkspur?

  In Larkspur, 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; Larkspur planning can confirm the exact process.

• Are there parking requirements for ADUs in Larkspur?

  In Larkspur, parking for ADUs is generally Often waived per state law; check local ordinance. California law often waives parking for ADUs within a half-mile of transit or in certain historic districts. Check with Larkspur planning for your address.