Modesto, Stanislaus County

ADU / Guest House Cost in Modesto, CA

Modesto remodeling costs are 20% belowthe California state average. Here's what a typical adu / guest house costs in Modesto in 2026, based on a 500 sqf project.

Budget
$100,000
$200/sqf
Mid-Range
$160,000
$320/sqf
High-End
$240,000
$480/sqf

Cost breakdown

Foundation & Framing
25%$40,000
Mechanical (HVAC, Plumbing, Electrical)
20%$32,000
Interior Finishes
20%$32,000
Exterior & Roofing
15%$24,000
Kitchen & Bath Fixtures
10%$16,000
Permits, Plans & Engineering
10%$16,000

Breakdown based on mid-range estimate of $160,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Modesto

Northern Central Valley city with very affordable remodeling. Many 1960s-70s homes due for updates. Hot summers make insulation and HVAC top priorities.

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 Modesto

Kitchen Remodel
$24,000 – $72,000
Bathroom Remodel
$12,000 – $38,400
Room Addition
$48,000 – $132,000
Roof Replacement
$10,000 – $30,000
Exterior Paint
$4,000 – $14,000
Whole House Remodel
$216,000 – $720,000

ADU / Guest House cost in other California cities

Ross
$175,000 – $420,000 | Marin County
Sacramento
$112,500 – $270,000 | Sacramento County
Santa Barbara
$150,000 – $360,000 | Santa Barbara County
Del Mar
$150,000 – $360,000 | San Diego County
Palm Springs
$118,750 – $285,000 | Riverside County
Bakersfield
$100,000 – $240,000 | Kern County
Poway
$125,000 – $300,000 | San Diego County
Ontario
$106,250 – $255,000 | San Bernardino County

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