Napa, Napa County

ADU / Guest House Cost in Napa, CA

Napa remodeling costs are 15% abovethe California state average. Here's what a typical adu / guest house costs in Napa in 2026, based on a 500 sqf project.

Budget
$143,750
$288/sqf
Mid-Range
$230,000
$460/sqf
High-End
$345,000
$690/sqf

Cost breakdown

Foundation & Framing
25%$57,500
Mechanical (HVAC, Plumbing, Electrical)
20%$46,000
Interior Finishes
20%$46,000
Exterior & Roofing
15%$34,500
Kitchen & Bath Fixtures
10%$23,000
Permits, Plans & Engineering
10%$23,000

Breakdown based on mid-range estimate of $230,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Napa

Wine country premium applies to remodeling costs. Earthquake damage from 2014 drove significant renovation activity. Many homes blending indoor-outdoor living with wine country aesthetics.

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 Napa

Kitchen Remodel
$34,500 – $103,500
Bathroom Remodel
$17,250 – $55,200
Room Addition
$69,000 – $189,750
Roof Replacement
$14,375 – $43,125
Exterior Paint
$5,750 – $20,125
Whole House Remodel
$310,500 – $1,035,000

ADU / Guest House cost in other California cities

Ross
$175,000 – $420,000 | Marin County
Danville
$150,000 – $360,000 | Contra Costa County
Corte Madera
$150,000 – $360,000 | Marin County
Santa Rosa
$137,500 – $330,000 | Sonoma County
Castro Valley
$137,500 – $330,000 | Alameda County
Benicia
$125,000 – $300,000 | Solano County
San Anselmo
$150,000 – $360,000 | Marin County
Sausalito
$162,500 – $390,000 | Marin County

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