Whittier

An Accessory Dwelling Unit (ADU) or Junior Accessory Dwelling Unit (JADU) is permitted in Whittier as part of residential development and is reviewed through the City’s Planning Division.

ADU and JADU applications include new construction (attached or detached) as well as conversions of garages or accessory structures.

Planning approval is required prior to the issuance of any building permit and projects may be subject to review by City staff, commissions or design review bodies depending on project scope.

• Detached ADU: New standalone structures are supported through preapproved plans offered by the city.
• Attached ADU: New construction attached to the primary residence is permitted through the ADU application process.
• Conversion ADU: Garage or accessory structure conversions into ADUs are permitted.
• Junior ADU (JADU): Allowed within the existing residence and processed through the ADU/JADU application.

• Maximum Size:
  
  • Detached ADUs can generally go up to 1,200 sq ft, but an 800 sq ft size is allowed regardless of lot size constraints. Attached ADUs are permitted up to 50% of the existing primary dwelling size.
    
    
• Setbacks:
  
  • Minimum 4 ft from side and rear property lines for ADUs
  • Exterior walls with openings must maintain minimum 5 ft setbacks
  • Minimum 5 ft separation required between structures
    
    
• Height Limits:
  
  • Detached: Maximum 16 ft
  • Attached: Height limitations of the zoning district or 25 feet high.
    
    
• Parking Requirements:
  
  • Additional parking is generally not required if the ADU qualifies under state exemptions:
    
    • No parking is required if the ADU is within ½ mile of public transit, located in a historic district, or constructed within an existing structure. 
    • Where existing covered parking (garage, carport, etc.) is demolished or converted in conjunction with ADU construction, replacement parking is not required.

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

• ADU/JADU application submission through the Planning Division
• Planning approval prior to building permit issuance
• Fire Flow Residential approval through the Engineering Division
• Site plan, title report, photographs and supporting documents
• Building Energy Analysis (Title 24 compliance)
• Additional reports or permits (e.g., sewer inspection, solar, fire sprinklers) as required

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

Applications submitted to the Planning Division are generally assigned for review within 7 to 14 working days. For preapproved ADU plans, the process is typically faster, beginning with an initial application completeness review that takes about 1 to 2 business days, followed by a plan check review of approximately 5 business days. If revisions are required, resubmittal reviews usually take an additional 5 business days. However, the City does not specify an overall total timeline for permit approval in the available sources. 

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

Properties must be located in residential zones that allow single-family use (such as R-E, H-R and R-1) and must contain an existing or proposed primary dwelling.

Projects must comply with zoning regulations, design guidelines and development standards outlined in the Whittier Municipal Code.

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

The Planning Services page outlines application procedures, approvals and zoning requirements, while the Preapproved ADU Plans page provides standardized ADU designs, submittal steps and permitting guidance to help streamline the process.