Danville, Contra Costa County

ADU / Guest House Cost in Danville, CA

Danville remodeling costs are 20% abovethe California state average. Here's what a typical adu / guest house costs in Danville in 2026, based on a 500 sqf project.

Budget

$150,000

$300/sqf

Mid-Range

$240,000

$480/sqf

High-End

$360,000

$720/sqf

Cost breakdown

Foundation & Framing

25%$60,000

Mechanical (HVAC, Plumbing, Electrical)

20%$48,000

Interior Finishes

20%$48,000

Exterior & Roofing

15%$36,000

Kitchen & Bath Fixtures

10%$24,000

Permits, Plans & Engineering

10%$24,000

Breakdown based on mid-range estimate of $240,000

Typical Timeline

4-8 months

Permits Required

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

Remodeling in Danville

Upscale Tri-Valley town with large homes and lots. Premium contractor rates but strong renovation ROI. Many homeowners doing high-end kitchen and outdoor living projects.

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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