Antioch, Contra Costa County

ADU / Guest House Cost in Antioch, CA

Antioch remodeling costs are nearthe California state average. Here's what a typical adu / guest house costs in Antioch in 2026, based on a 500 sqf project.

Budget
$118,750
$238/sqf
Mid-Range
$190,000
$380/sqf
High-End
$285,000
$570/sqf

Cost breakdown

Foundation & Framing
25%$47,500
Mechanical (HVAC, Plumbing, Electrical)
20%$38,000
Interior Finishes
20%$38,000
Exterior & Roofing
15%$28,500
Kitchen & Bath Fixtures
10%$19,000
Permits, Plans & Engineering
10%$19,000

Breakdown based on mid-range estimate of $190,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Antioch

Most affordable Bay Area city for remodeling. East County location with newer housing stock. Hot Delta climate makes energy efficiency and HVAC critical project components.

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 Antioch

Kitchen Remodel
$28,500 – $85,500
Bathroom Remodel
$14,250 – $45,600
Room Addition
$57,000 – $156,750
Roof Replacement
$11,875 – $35,625
Exterior Paint
$4,750 – $16,625
Whole House Remodel
$256,500 – $855,000

ADU / Guest House cost in other California cities

Burbank
$125,000 – $300,000 | Los Angeles County
Escondido
$112,500 – $270,000 | San Diego County
Hayward
$131,250 – $315,000 | Alameda County
Rancho Cucamonga
$112,500 – $270,000 | San Bernardino County
Daly City
$150,000 – $360,000 | San Mateo County
Thousand Oaks
$131,250 – $315,000 | Ventura County
Redwood City
$156,250 – $375,000 | San Mateo County
San Marcos
$118,750 – $285,000 | San Diego County

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