Petaluma, Sonoma County

ADU / Guest House Cost in Petaluma, CA

Petaluma remodeling costs are 10% abovethe California state average. Here's what a typical adu / guest house costs in Petaluma in 2026, based on a 500 sqf project.

Budget
$137,500
$275/sqf
Mid-Range
$220,000
$440/sqf
High-End
$330,000
$660/sqf

Cost breakdown

Foundation & Framing
25%$55,000
Mechanical (HVAC, Plumbing, Electrical)
20%$44,000
Interior Finishes
20%$44,000
Exterior & Roofing
15%$33,000
Kitchen & Bath Fixtures
10%$22,000
Permits, Plans & Engineering
10%$22,000

Breakdown based on mid-range estimate of $220,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Petaluma

Southern Sonoma County city with historic downtown and charming residential neighborhoods. Mix of Victorian, Craftsman, and mid-century homes. Growing demand from SF remote workers renovating homes.

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 Petaluma

Kitchen Remodel
$33,000 – $99,000
Bathroom Remodel
$16,500 – $52,800
Room Addition
$66,000 – $181,500
Roof Replacement
$13,750 – $41,250
Exterior Paint
$5,500 – $19,250
Whole House Remodel
$297,000 – $990,000

ADU / Guest House cost in other California cities

Sacramento
$112,500 – $270,000 | Sacramento County
El Monte
$112,500 – $270,000 | Los Angeles County
Hermosa Beach
$150,000 – $360,000 | Los Angeles County
San Clemente
$137,500 – $330,000 | Orange County
Calabasas
$143,750 – $345,000 | Los Angeles County
Sherman Oaks
$131,250 – $315,000 | Los Angeles County
San Diego
$125,000 – $300,000 | San Diego County
Downey
$118,750 – $285,000 | Los Angeles County

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