City ADU planning guide

Signal Hill ADU regulations and next steps

Start with the most important planning decisions, then review the detailed city rules below before choosing a detached ADU plan or requesting a property-specific feasibility review.

Signal Hill ADU rules overview

Detailed local requirements vary by property. Use this section as a starting point for setbacks, parking, height, utilities, and approval considerations.

Lot fit

Setbacks and buildable area

Start with rear and side setbacks, lot coverage, access, and where a detached ADU can realistically sit on the property.

Design limits

Size, height, and unit type

Check whether the property is better suited for a detached ADU, attached ADU, garage conversion, or junior ADU.

Approvals

Parking, utilities, and permits

Confirm parking exemptions, utility connection requirements, impact fees, and city review steps before finalizing plans.

Signal Hill, CA, follows California's state ADU regulations with some localized adjustments. Here's a detailed overview of ADU regulations in Signal Hill:

Types of ADUs Permitted:

  • Detached ADUs Freestanding units separate from the main residence.
  • Attached ADUs Units attached to the primary residence, sharing at least one wall.
  • Garage Conversions Conversion of existing garages into ADUs.
  • Junior ADUs (JADUs) Units up to 500 sq. ft., located within the primary dwelling, with an efficiency kitchen and separate entrance.

Zoning and Lot Requirements:

  • ADUs are allowed in all residential zones, including single-family (R-1) and multi-family (R-2, R-3).
  • No minimum lot size requirements for ADUs, per California state law.

Size Limits:

  • Detached ADUs Up to 1,200 sq. ft., or 10% of the lot area, whichever is smaller.
  • Attached ADUs Maximum 50% of the floor area of the main residence, up to 1,200 sq. ft.
  • JADUs Maximum of 500 sq. ft.
  • Minimum size for any ADU is 150 sq. ft., per California Building Code.

Setbacks:

  • Side and rear setbacks Minimum of 4 feet for new detached ADUs.
  • No setbacks required for conversion ADUs created within an existing structure (e.g., garages or accessory buildings).
  • Front setbacks must comply with existing zoning standards for the primary structure.

Height Limits:

  • One-story ADUs Up to 16 feet.
  • Two-story ADUs Up to 18 feet in certain zones, or higher depending on proximity to transit corridors or lot topography.

Parking Requirements:

  • No Parking Required
    • If the ADU is located within ½ mile of public transit.
    • If the ADU is part of a garage conversion.
    • If located in an area where on-street parking permits are required but not provided to the occupants.
  • If parking is required One space per ADU or bedroom, which can be tandem or in driveways.

Owner-Occupancy:

  • For ADUs No owner-occupancy requirement through January 1, 2025, per state law.
  • For JADUs The owner must live in either the JADU or the primary residence.

Utilities and Fees:

  • Utility Connections
    • New utility connections are required for detached ADUs.
    • Attached ADUs and JADUs may use existing utility connections without additional fees.
  • Impact Fees
    • Waived for ADUs under 750 sq. ft.
    • Larger ADUs may incur proportional impact fees based on their size relative to the main dwelling.

Design Standards:

  • Architectural Compatibility The ADU should match the style, roofline, and exterior materials of the primary residence.
  • Privacy Standards Placement of windows and doors should respect neighboring properties, and landscaping may be required for screening.
  • Open Space Requirements ADUs should not reduce the usable open space on the lot below the minimum required by zoning regulations.

Permitting Process:

  • Streamlined Permitting
    • Applications must be approved within 60 days if compliant with zoning and building standards.
  • Required Documents
    • Site plan indicating lot dimensions, setbacks, and ADU location.
    • Floor plans, elevations, and details of the proposed ADU.
    • Proof of compliance with Signal Hill zoning and building codes.

Additional Considerations:

  • Historic Properties ADUs on historically designated properties may have additional design restrictions.
  • Green Building Standards
    • Compliance with energy efficiency requirements, including potential solar panel installations, is mandatory for new construction.
  • Affordable Housing Signal Hill may incentivize ADUs rented at affordable rates.

Next Steps:

  • Check Property Eligibility
    • Use Signal Hill’s zoning map or contact the Planning Department to verify your lot’s requirements.
  • Plan Development
    • Hire an architect or designer familiar with Signal Hill’s ADU regulations to ensure compliance.
  • Pre-Application Meeting
    • Schedule a consultation with the Planning Department to address any preliminary questions.
  • Submit Application
    • Complete the application process, including all required documentation and fees.
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