A Comprehensive Guide to Union City ADU Rules

Accessory Dwelling Units (ADUs) offer a practical solution for adding extra living space, generating rental income, or housing extended family members. However, building an ADU requires navigating specific regulations. This guide covers the essential Union City ADU rules to help you plan your project effectively and ensure compliance.

Key Union City ADU Rules and Requirements

Permits and Approvals

• Building Permit: You will need a building permit for all ADUs in Union City. This ensures the construction meets local building codes.
• Planning Approval: ADUs must comply with the local zoning code. Planning approval is needed to ensure the ADU aligns with zoning, lot size, and usage regulations.

Size Requirements:

• Detached ADUs: The maximum floor area is 1,200 square feet. Detached units must be smaller than the primary dwelling.
• Attached ADUs: The maximum size for an attached ADU is either 800 square feet or 50% of the primary residence, whichever is smaller.
• Junior ADUs: Junior ADUs (JADUs) are limited to 500 square feet and must be within the existing footprint of the primary home.

Usage and Occupancy

• Primary Residence: ADUs must function as secondary living spaces. They cannot be sold separately from the main house.
• Occupancy: ADUs can be used for long-term rentals but cannot be used as short-term vacation rentals (less than 30 days).
• Owner Occupancy: As of 2020, owner occupancy is not required in Union City for newly constructed ADUs until January 1, 2025.

Design Standards

• Architectural Consistency: ADUs must match the architectural style of the primary residence, including roof pitch, exterior materials, and colors.
• Height Restrictions: For single-story ADUs, the maximum height is 16 feet. For ADUs with two stories, a height limit of 18 feet applies.
• Setbacks: Union City requires a minimum setback of 4 feet from the rear and side property lines for detached ADUs.

Parking Requirements

• Parking: One parking space is required for ADUs unless the ADU is within half a mile of public transit, part of the existing primary structure, or located within a historic district.
• Exemptions: No additional parking is required if the ADU is converted from a garage, carport, or covered parking structure.

Utility Connections

• Water and Sewer: ADUs must connect to the existing utility lines of the primary residence. Separate meters are optional but may be required for detached units.
• Energy Efficiency: ADUs must comply with California’s Title 24 energy standards, which mandate energy-efficient windows, insulation, and appliances.

Setback and Lot Coverage Requirements

• Lot Coverage: ADUs must comply with the overall lot coverage requirements, which typically limit building coverage to 40-50% of the lot area.
• Separation: A minimum distance of 10 feet is required between the ADU and the primary residence. For fire safety, this distance can affect the location of windows and doors.

Additional Regulations

• Fire Safety: ADUs must have smoke detectors, carbon monoxide detectors, and possibly sprinklers, depending on size and location.
• Easements: ADUs must respect existing easements on the property and cannot obstruct access to public utilities.
• Noise and Privacy: Soundproofing may be required, especially for attached ADUs. Fencing or landscaping can provide privacy between the ADU and neighboring properties.

Steps to Getting Started

• Consult the Planning Department: Review your property’s zoning and assess the feasibility of adding an ADU.
• Prepare Your Plans: Work with a licensed architect or designer to create plans that comply with Union City regulations.
• Submit Your Application: Apply for the necessary permits, including building, planning, and utility connections.
• Start Construction: Once approved, construction can begin. Ensure all work is inspected and meets code requirements.

Building an ADU offers numerous benefits, from additional living space to increased property value. By following local regulations and planning your project carefully, you can create a functional and compliant ADU that meets your needs.

For more detailed information and to start your project, visit the Union City Planning Department’s website or consult a local expert familiar with ADU regulations.