Downey, Los Angeles County

ADU / Guest House Cost in Downey, CA

Downey remodeling costs are nearthe California state average. Here's what a typical adu / guest house costs in Downey 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 Downey

Southeast LA with affordable remodeling costs. Many 1950s-60s homes being updated by young families. The city's building department is relatively efficient.

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 Downey

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

Lafayette
$150,000 – $360,000 | Contra Costa County
Escondido
$112,500 – $270,000 | San Diego County
Dublin
$137,500 – $330,000 | Alameda County
Foster City
$156,250 – $375,000 | San Mateo County
Lake Forest
$131,250 – $315,000 | Orange County
Napa
$143,750 – $345,000 | Napa County
Hermosa Beach
$150,000 – $360,000 | Los Angeles County
Ontario
$106,250 – $255,000 | San Bernardino County

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