Simi Valley, Ventura County

ADU / Guest House Cost in Simi Valley, CA

Simi Valley remodeling costs are nearthe California state average. Here's what a typical adu / guest house costs in Simi Valley in 2026, based on a 500 sqf project.

Budget
$118,750
$238/sqf
Mid-Range
$190,000
$380/sqf
High-End
$285,000
$570/sqf

Cost breakdown

Foundation & Framing
25%$47,500
Mechanical (HVAC, Plumbing, Electrical)
20%$38,000
Interior Finishes
20%$38,000
Exterior & Roofing
15%$28,500
Kitchen & Bath Fixtures
10%$19,000
Permits, Plans & Engineering
10%$19,000

Breakdown based on mid-range estimate of $190,000

Typical Timeline
4-8 months
Permits Required

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

Remodeling in Simi Valley

Suburban Ventura County city with affordable remodeling by Southern California standards. Many 1970s-80s homes being updated. Hot summers drive HVAC and pool demand.

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 Simi Valley

Kitchen Remodel
$28,500 – $85,500
Bathroom Remodel
$14,250 – $45,600
Room Addition
$57,000 – $156,750
Roof Replacement
$11,875 – $35,625
Exterior Paint
$4,750 – $16,625
Whole House Remodel
$256,500 – $855,000

ADU / Guest House cost in other California cities

Pasadena
$137,500 – $330,000 | Los Angeles County
Walnut Creek
$143,750 – $345,000 | Contra Costa County
Corte Madera
$150,000 – $360,000 | Marin County
Benicia
$125,000 – $300,000 | Solano County
Vallejo
$118,750 – $285,000 | Solano County
Sonoma
$143,750 – $345,000 | Sonoma County
Larkspur
$156,250 – $375,000 | Marin County
Rancho Cucamonga
$112,500 – $270,000 | San Bernardino County

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