Santa Monica

Santa Monica allows ADUs on residential properties in compliance with California state law, with additional local standards related to design, zoning and coastal considerations.

• ADUs are generally permitted on lots with existing or proposed residential uses
• Both Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs) are allowed
• ADUs may be created within existing structures or as new construction
• Santa Monica applies objective standards but must allow state-mandated ADU approvals
• One JADU is permitted on each residential lot. The JADU shall not be considered a separate or a new dwelling unit for the purposes of applying building or fire codes.
  

Santa Monica aligns with California’s broader ADU legislation but has its own requirements for height, setbacks and design review.

• Detached ADU: A standalone residential unit located on the same lot as the primary dwelling
• Attached ADU: A unit attached to the primary residence and sharing at least one wall
• Conversion ADU: Created from existing structures such as garages or accessory buildings, or from portions of the primary residence
• Junior ADU (JADU): A smaller unit (maximum 500 sq. ft.) located within an existing or proposed single-family home, including an efficiency kitchen and possibly shared bathroom facilities

• Maximum Size:
  
  • Detached: 
• Up to 800 sq. ft. minimum allowed regardless of lot size or zoning constraints
• Larger sizes may be allowed depending on lot and zoning standards
  
  • Attached: 
• Up to 50% of the primary dwelling’s floor area
• Must allow at least 800 sq. ft.
  
  
• Setbacks:
  
  • Minimum 4 feet from side and rear property lines for detached and attached ADUs
  • Conversions of existing structures may have reduced or no setback requirements
    
    
• Height Limits:
  
  • Detached: 
• Typically up to 16 feet minimum allowed
• May increase depending on zoning, proximity to transit, or if above garage
  
  • Attached: Subject to underlying zoning height limits
    
    
• Parking Requirements:
  
  • No parking required if:
    
    • Located within ½ mile of public transit 
    • Located in a historic district
• Part of an existing structure conversion
  
  • Replacement parking is not required if existing parking is removed for ADU construction

To build an ADU in Santa Monica, the following approvals and submittals are typically required:

• Building permit application
• Zoning compliance review
• Architectural/design review
• Utility connection and impact fees
• Compliance with building and fire codes

Homeowners should also review Santa Monica current fee schedule, utility connection requirements and fire code compliance.

ADU applications in Santa Monica must be reviewed within 60 days if the submission is complete, as required by California state law. However, the actual timeline for approval can vary depending on several factors, including whether the application is fully complete at the time of submission, the extent of any plan check corrections that may be required and the overall complexity of the proposed project.  

Engaging professionals familiar with Santa Monica ADU process can help streamline approval and potentially reduce delays.

In Santa Monica, ADUs are permitted within residential zoning districts and are allowed on both single-family and multifamily properties. There is no minimum lot size required to establish at least one ADU, consistent with California state standards. However, additional regulations may apply depending on the property’s location, particularly within coastal zones, historic districts, or areas governed by specific plans, where further restrictions or design considerations may be required.

For the most current and complete information, refer directly to the City of Santa Monica.

Including the Housing Progress Dashboard, which offers updated data on the City’s housing production and ADU activity, the Accessory Dwelling Unit Handbook that compiles guidance on regulations and development pathways and the ADU Conversion Information Bulletin issued by the Building & Safety Division, which outlines requirements for converting existing structures into ADUs. These resources collectively provide both technical standards and broader housing context to support ADU planning and development.