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Local ADU Rules

Larkspur

Last Updated May 21, 2025

ADU Contact:

Larkspur Planning Department planning@cityoflarkspur.org

Standards	Details
Zones allowed	All residential and mixed-use zones with limited exceptions, except MHP.
Lot Restrictions	Restricted areas include Very High Fire Hazard Severity Zones with constrained roadway for emergency vehicles; Map on file with City.
Minimum Lot Size	Minimum: 150 square feet Maximum: 850 square feet for studio/one bedroom. 1000 square feet for two bedrooms. 1200 square feet or 50% of the existing or remaining habitable floor space of the primary dwelling, whichever is less. JADUs Maximum: 500 square feet One ADU and one JADU allowed on each single-family property. Also allowed on multifamily properties under state law. Number of bedrooms is dependent upon square footage (see above).
Min/Max ADU Size
ADU Building Height	Up to 16 feet if detached and less than 800 square feet. Otherwise up to 15 feet if detached or 30 feet if attached.
Setbacks	None for conversions of existing living area or structure and 4-foot side and rear setbacks for attached or detached ADUs no more than 800 square feet and 16 feet in height. Side and rear setbacks must meet fire safety requirements.
Parking Requirements	One parking space per ADU unless 1) within ½ mile of transit, historic district or car share, 2) created by converting or demolishing garage or carport or 3) less than 800 square feet, then none required. Tandem parking and parking in setbacks are both allowed.
Owner Occupancy	Not required for ADU or primary residence. Required for JADU.
Sample fees from recent permits	Example 1: 275 sf detached ADU Valuation: $100,000 Permit fees: $5,744 Example 2: 397 sf converted storage space JADU Valuation: $40,000 Permit fees: $3,389 *Fees are specific to each project and will vary. Fees change regularly. These are provided as examples only.
Other requirements	A deed restriction must be filed that includes ADU or JADU shall not be sold separate from primary dwelling unit, which is binding for future owners. If ADU is eliminated, re-instatement of parking space and observance of zoning regulations for single-family use is required, as applicable. Fire Sprinklers: Needed if required for primary residence. Historic Preservation: requirements remain for sites included on Local Historic Resource Inventory and/or within Downtown Historic District.
Process	Complete applications reviewed by City within 60 days per State law. Building Permit only, with concurrent zoning clearance approval. Disclaimer: standards and process may vary. Consultation with the contact is recommended before starting any project.
Exceptions	No FAR or Coverage restrictions for ADUs of no more than 800 square and 16 feet in height (Per State Law).

Wondering what you can build?

Make sure you check out our Learning the Rules page for more step-by-step details