Union City, Alameda County

ADU / Guest House Cost in Union City, CA

Union City remodeling costs are 10% abovethe California state average. Here's what a typical adu / guest house costs in Union City in 2026, based on a 500 sqf project.

Budget
$137,500
$275/sqf
Mid-Range
$220,000
$440/sqf
High-End
$330,000
$660/sqf

Cost breakdown

Foundation & Framing
25%$55,000
Mechanical (HVAC, Plumbing, Electrical)
20%$44,000
Interior Finishes
20%$44,000
Exterior & Roofing
15%$33,000
Kitchen & Bath Fixtures
10%$22,000
Permits, Plans & Engineering
10%$22,000

Breakdown based on mid-range estimate of $220,000

Typical Timeline
4-8 months
Permits Required

Building, electrical, plumbing, mechanical. May require plan check.

Remodeling in Union City

Growing East Bay city between Fremont and Hayward. Many 1970s-80s homes ready for kitchen and bathroom updates. Reasonable costs by Bay Area standards.

California allows ADUs on most residential lots since 2020. An ADU adds living space and rental income. Cities must approve or deny within 60 days of a complete application.

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Other projects in Union City

Kitchen Remodel
$33,000 – $99,000
Bathroom Remodel
$16,500 – $52,800
Room Addition
$66,000 – $181,500
Roof Replacement
$13,750 – $41,250
Exterior Paint
$5,500 – $19,250
Whole House Remodel
$297,000 – $990,000

ADU / Guest House cost in other California cities

Foster City
$156,250 – $375,000 | San Mateo County
West Hollywood
$150,000 – $360,000 | Los Angeles County
South San Francisco
$150,000 – $360,000 | San Mateo County
Escondido
$112,500 – $270,000 | San Diego County
Livermore
$131,250 – $315,000 | Alameda County
Fremont
$143,750 – $345,000 | Alameda County
El Monte
$112,500 – $270,000 | Los Angeles County
Encinitas
$137,500 – $330,000 | San Diego County

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