Millbrae, San Mateo County

ADU / Guest House Cost in Millbrae, CA

Millbrae remodeling costs are 20% abovethe California state average. Here's what a typical adu / guest house costs in Millbrae 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 Millbrae

Near SFO and BART, making it accessible for contractors. Many homes from the 1950s-60s are being modernized. Strong Asian-American community drives demand for specific kitchen features like wok ranges and large pantries.

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 Millbrae

Kitchen Remodel
$36,000 – $108,000
Bathroom Remodel
$18,000 – $57,600
Room Addition
$72,000 – $198,000
Roof Replacement
$15,000 – $45,000
Exterior Paint
$6,000 – $21,000
Whole House Remodel
$324,000 – $1,080,000

ADU / Guest House cost in other California cities

Berkeley
$156,250 – $375,000 | Alameda County
Costa Mesa
$131,250 – $315,000 | Orange County
Fairfax
$143,750 – $345,000 | Marin County
San Ramon
$143,750 – $345,000 | Contra Costa County
Los Angeles
$131,250 – $315,000 | Los Angeles County
Concord
$125,000 – $300,000 | Contra Costa County
Santa Monica
$150,000 – $360,000 | Los Angeles County
Moraga
$150,000 – $360,000 | Contra Costa County

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