Los Altos Hills, Santa Clara County

ADU / Guest House Cost in Los Altos Hills, CA

Los Altos Hills remodeling costs are 40% abovethe California state average. Here's what a typical adu / guest house costs in Los Altos Hills in 2026, based on a 500 sqf project.

Budget
$175,000
$350/sqf
Mid-Range
$280,000
$560/sqf
High-End
$420,000
$840/sqf

Cost breakdown

Foundation & Framing
25%$70,000
Mechanical (HVAC, Plumbing, Electrical)
20%$56,000
Interior Finishes
20%$56,000
Exterior & Roofing
15%$42,000
Kitchen & Bath Fixtures
10%$28,000
Permits, Plans & Engineering
10%$28,000

Breakdown based on mid-range estimate of $280,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Los Altos Hills

Ultra-premium hillside community with 1+ acre lots. Estate-scale renovations are common. Grading, septic, and hillside construction add significant cost. Limited road access can complicate material delivery.

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 Hills

Kitchen Remodel
$42,000 – $126,000
Bathroom Remodel
$21,000 – $67,200
Room Addition
$84,000 – $231,000
Roof Replacement
$17,500 – $52,500
Exterior Paint
$7,000 – $24,500
Whole House Remodel
$378,000 – $1,260,000

ADU / Guest House cost in other California cities

Palm Springs
$118,750 – $285,000 | Riverside County
Belmont
$156,250 – $375,000 | San Mateo County
Concord
$125,000 – $300,000 | Contra Costa County
Pittsburg
$118,750 – $285,000 | Contra Costa County
Lafayette
$150,000 – $360,000 | Contra Costa County
Union City
$137,500 – $330,000 | Alameda County
San Rafael
$150,000 – $360,000 | Marin County
Fairfax
$143,750 – $345,000 | Marin County

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