ADU Construction in Union City
Union City is a strong market for ADU construction, with options ranging from $150K for a garage conversion to $475K+ for a large detached unit. Custom Home builds detached, attached, and garage conversion ADUs in Union City with full 3D visualization and itemized pricing through our two-phase process.
How much does an ADU cost in Union City?
Union City ADU costs range from $150K-$250K for a garage conversion to $250K-$475K for a detached unit in 2026. Custom Home's two-phase process provides 3D visualization and exact pricing before construction begins.
Why Union City is a Strong Market for ADU Construction
Union City offers practical conditions for ADU construction, with competitive build costs and solid rental demand. Many homeowners recoup their ADU investment through rental income within several years. The East Bay’s combination of value and lifestyle continues to attract quality-minded homeowners.
Custom Home builds ADUs in Union City with the same two-phase design-build process we use for custom homes. You see the complete design in 3D and receive itemized pricing before any construction begins.
Types of ADUs We Build in Union City
Detached ADUs
A standalone structure in your backyard, typically 400-1,200 sqft. Detached ADUs offer the most privacy and design flexibility. They work well for rental units, home offices, or multigenerational living. Construction costs in Union City typically range from $250K to $475K.
Attached ADUs
Built as an addition to your existing home, sharing at least one wall. Attached ADUs are typically more cost-effective than detached units since they share structural elements with the main house. They are a good fit for family members who want proximity while maintaining separate living spaces.
Garage Conversions
Converting an existing garage into a living space is the most affordable ADU option in Union City, starting from $150K. Since the structure already exists, you save on foundation, framing, and roofing costs.
Union City ADU Permitting
Union City’s Building Division processes residential construction permits with typical plan review times of 3-6 weeks. The city accepts applications in person and offers pre-application consultations to help homeowners understand requirements before submitting plans.
Custom Home manages the entire ADU permitting process in Union City, preparing plans that meet local requirements for efficient review and approval.
ADU Rental Income Potential in Union City
Union City’s rental market supports strong returns for ADU owners. Estimated monthly rental rates:
- Studio/1-bedroom (400-600 sqft): $2,000-$2,500/month
- 1-bedroom (600-800 sqft): $2,400-$2,900/month
- 2-bedroom (800-1,200 sqft): $2,700-$3,200/month
At these rates, many ADU investments pay for themselves within 7-12 years through rental income alone, not counting the property value increase that a permitted ADU provides.
Pricing for ADU Construction in Union City
Union City ADU construction costs range from $150K for a basic garage conversion to $475K+ for a large detached unit with premium finishes. Per-square-foot costs typically run $325-$500/sqft. Garage conversions are the most cost-effective option since the structure already exists. Custom Home provides itemized pricing during Phase 1 so you know every cost before committing.
Union City Permit Requirements
Union City's Building Division processes residential construction permits with typical plan review times of 3-6 weeks. The city accepts applications in person and offers pre-application consultations to help homeowners understand requirements before submitting plans. Custom Home handles the entire ADU permitting process, preparing plans that meet local requirements for efficient approval.
ADU Construction in Union City: FAQ
What does ADU construction cost in Union City?
ADU costs in Union City range from $150K for a garage conversion to $475K+ for a large detached unit. The biggest cost factors are ADU type, size, finishes, and utility connections. Custom Home provides itemized pricing during Phase 1 so you know every cost upfront.
How long does it take to build an ADU in Union City?
ADU construction in Union City typically takes 6-12 months from design to move-in. Garage conversions are fastest at 4-6 months, while detached units take 8-12 months including permits. Custom Home's design phase front-loads decisions to keep construction on schedule.
Can I rent out my ADU in Union City?
Yes. California law allows ADU rentals, and Union City does not require owner-occupancy. Many homeowners earn $2,000-$3,200/month in rental income from their ADU, making it a strong investment.