Los Altos, Santa Clara County

ADU / Guest House Cost in Los Altos, CA

Los Altos remodeling costs are 35% abovethe California state average. Here's what a typical adu / guest house costs in Los Altos in 2026, based on a 500 sqf project.

Budget
$168,750
$338/sqf
Mid-Range
$270,000
$540/sqf
High-End
$405,000
$810/sqf

Cost breakdown

Foundation & Framing
25%$67,500
Mechanical (HVAC, Plumbing, Electrical)
20%$54,000
Interior Finishes
20%$54,000
Exterior & Roofing
15%$40,500
Kitchen & Bath Fixtures
10%$27,000
Permits, Plans & Engineering
10%$27,000

Breakdown based on mid-range estimate of $270,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Los Altos

Premium residential community between Palo Alto and Cupertino. Home values justify major renovations. Many 1950s ranch homes being transformed with modern additions and high-end kitchens.

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 Los Altos

Kitchen Remodel
$40,500 – $121,500
Bathroom Remodel
$20,250 – $64,800
Room Addition
$81,000 – $222,750
Roof Replacement
$16,875 – $50,625
Exterior Paint
$6,750 – $23,625
Whole House Remodel
$364,500 – $1,215,000

ADU / Guest House cost in other California cities

Palm Desert
$118,750 – $285,000 | Riverside County
San Jose
$156,250 – $375,000 | Santa Clara County
Cupertino
$162,500 – $390,000 | Santa Clara County
San Leandro
$137,500 – $330,000 | Alameda County
Campbell
$150,000 – $360,000 | Santa Clara County
San Mateo
$156,250 – $375,000 | San Mateo County
Fremont
$143,750 – $345,000 | Alameda County
Lafayette
$150,000 – $360,000 | Contra Costa County

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