Santa Monica ADU: Regulations, Costs & Permits

The city lets you choose a track. A Santa Monica Permitted ADU uses the city's more generous local standards, with design rules attached. A State Mandated ADU uses the minimum state rules (a detached unit up to 800 sq ft with 4 ft side and rear setbacks), and the city can't add other standards. Picking the right track for your lot is one of the first decisions.

• Unit count on a single-family lot: one converted ADU, one JADU, and one detached ADU. In the R1 zone you can add one more ADU, attached or detached. That extra R1 unit has to be deed-restricted as a rental or sold as a condo.
• Size on the local track: 150 sq ft minimum. Up to 850 sq ft for a studio or one-bedroom, and 1,200 sq ft for two or more bedrooms. An attached garage with an interior connection doesn't count toward the cap.
• Conversions and attached units: capped at 50% of the existing house or the size limit, whichever is less, but a conversion of existing house space is always allowed at least 800 sq ft.
• Height on the local track: a detached ADU can go 2 stories or 24 ft. An attached ADU follows the zone's height limit for the house. You need a land survey for anything over one story or on a sloped lot.
• Setbacks: 4 ft side and rear, none in the front setback, and 4 ft between a detached ADU and the house. Converting existing space or rebuilding in the same footprint needs no setback, including unpermitted structures built before 2020.
• Floor area: ADUs and JADUs don't count toward the lot's floor area, though a garage or storage space without an interior connection does.

• Access: the ADU needs its own exterior entrance and no interior door into the main house.
• Upper floors: the zone's upper-story stepback and upper-story outdoor space rules apply.
• Projections: nothing closer than 4 ft to a property line unless the code allows it.
• Parking: none required. Parking removed to build the ADU doesn't have to be replaced, and it can move to the front half of the lot if it meets standards.

• Coastal Zone: lots in the Coastal Zone may need a Coastal Development Permit or a waiver from the California Coastal Commission, handled before the building permit. The city suggests asking the Coastal Commission about parking there.
• Historic properties: only properties on the California Register of Historical Resources can face extra ADU standards or process.

• No design review or hearing: ADUs and JADUs are ministerial, needing only a building permit plus any Coastal Commission approval.
• 60-day decision: on a lot with an existing home, the city must approve or deny a complete application within 60 days or it's deemed approved.
• Online submittal: you open the application in Citizen Access and upload plans to ProjectDox. Review starts once plan review fees are paid, and permits are issued in person or by virtual appointment.
• Address: each ADU needs its own address, requested through a separate address application.
• Preapproved plans: the city runs a preapproved detached ADU program, but its list currently shows no approved plans.

• City impact fees: ADUs and JADUs are exempt from the city's affordable housing, child care, transportation, and parks impact fees.
• Public Works fees: ADUs over 750 sq ft may owe Public Works impact fees.
• Water and sewer: water capital fees apply only if you need a new or larger meter. Wastewater fees depend on the bedrooms you add.
• School fees: collected by Santa Monica-Malibu Unified through its developer fee program.

• No short-term rentals: ADUs can't be rented for 30 days or less, except as hosted home-sharing where the host lives in that same unit for the whole stay. Vacation rentals without a host are banned.
• Rent control: newly built units are generally eligible for the Rent Control Board's new construction exemption, which the Board has to grant. Units created by converting existing space don't qualify. Talk to the Rent Control Department before you plan a rental.
• Selling separately: Santa Monica allows ADUs to be sold as condominiums, with a condo association, a subdivision map, a safety inspection, and lender consent. JADUs can't be sold separately.
• Owner occupancy: not required for ADUs. For a JADU, the owner must live in the main house or the JADU.

How big can an ADU be in Santa Monica?

On the city's local track, up to 850 sq ft for a studio or one-bedroom and 1,200 sq ft for two or more bedrooms. On the state track, a detached ADU is up to 800 sq ft.

How many ADUs can I build on an R1 lot in Santa Monica?

Up to a converted ADU, a JADU, a detached ADU, and one more attached or detached ADU. The extra R1 unit has to be deed-restricted as a rental or sold as a condo.

Can I sell my Santa Monica ADU separately?

Yes. Santa Monica allows ADU condo sales under its local condo ordinance, which requires forming a condo association, a subdivision map, a safety inspection, and lender consent.

Can I Airbnb my ADU in Santa Monica?

Only as hosted home-sharing, with the host living in the unit for the whole stay. Rentals of 30 days or less without a host present are prohibited.

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