Monte Sereno

South El Monte allows ADUs and JADUs on legal residential parcels and follows California state law standards where applicable. ADUs are permitted in residential zones (R-1, R-2, R-3 and certain mixed-use zones) and are typically approved ministerially when they meet zoning and building requirements. 

ADUs must include independent access and comply with building and safety codes.

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

• Detached ADU: Allowed as a separate structure on the same lot
• Attached ADU: Allowed as an addition to the primary dwelling
• Conversion ADU: Allowed within existing space such as a garage or portion of the home
• Junior ADU (JADU): Allowed within the primary residence (typically smaller units)

• Maximum Size:
  
  • Detached: Up to 850 sq ft (1-bedroom) or 1,000 sq ft (2+ bedrooms)
  • Attached: Cannot exceed 50% of the primary dwelling’s floor area
    
    
• Setbacks:
  
  • Side and rear setbacks required for fire safety; generally, up to 4 feet for detached ADUs
    
    
• Height Limits:
  
  • Detached: Maximum 16 ft
  • Attached: Typically governed by the underlying zoning district, with detached ADUs often limited to around 16 ft, while state law may allow up to 25 ft when specific setback conditions are met.
    
    
• Parking Requirements:
  
  • One on-site parking space is generally required
  • Parking is not required if the ADU meets state exemption conditions (e.g., proximity to transit, conversions)
  • No replacement parking required when converting existing structures such as garages

• ADUs are approved ministerially when meeting applicable standards
• Building permits and plan check are required prior to construction
• Must comply with all building, fire and safety codes
• Plans may require review for electrical, mechanical and plumbing systems

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

ADU applications are processed ministerially, meaning approvals are handled administratively without discretionary hearings when all requirements are met. 

Engaging professionals familiar with Monte Sereno ADU process can help streamline approval and potentially reduce delays.

ADUs are permitted on legal parcels in residential zones including R-1, R-2 and R-3 districts. They must be located on a lot with an existing or proposed primary dwelling and comply with zoning code development standards.

For the most current and complete information, refer directly to the City of Monte Sereno.

ADU regulations are constantly evolving and may vary by city, county, or even neighborhood. Before starting your project, it’s always best to consult with a trained professional or certified ADU Specialist to ensure your plans align with current local requirements.