FOR HOMEOWNERS
How Much Does a Prefab ADU Actually Cost in 2026?
Before you build a backyard office, you want to know if the numbers actually work. Here's an honest breakdown of what it costs
Apr 22, 2026
8 min read
01
BACKYARD OFFICE
Apr 15 · 5 min
The Unit Itself: $22,000–$35,000
Includes all structural framing, exterior cladding, roofing, windows, doors, interior finishes, cabinetry, fixtures, electrical panel, plumbing rough-in, HVAC rough-in, and HCD certification. Price varies by square footage, finish level, and options.
Delivery and Placement: $1,500–$4,000
Costs depend on your distance from our facility and lot accessibility. Crane placement (for tight lots) adds cost. Most California deliveries fall in the $2,000–$3,000 range.
Site Preparation: $3,000–$15,000
The widest range and most variable category. Foundation ($2,000–$8,000), utility connections ($5,000–$8,500 combined), grading and drainage (if needed: $2,000–$8,000). The single biggest variable: how close your utilities are to the ADU site.
Total Project Cost Ranges
Simple lot, minimal site work: $28,000–$36,000. Average California lot: $36,000–$40,000. Complex lot: $52,000–$54,000. Still a fraction of the $120,000–$200,000+ cost of a custom ADU build in California today.
The $22,000 starting price is real — but it’s not the whole picture. Here’s an honest breakdown of what a prefab ADU costs from start to finish, including the numbers most builders don’t show you upfront.
The Unit Itself: $22,000–$35,000
Includes all structural framing, exterior cladding, roofing, windows, doors, interior finishes, cabinetry, fixtures, electrical panel, plumbing rough-in, HVAC rough-in, and HCD certification. Price varies by square footage, finish level, and options.
Delivery and Placement: $1,500–$4,000
Costs depend on your distance from our facility and lot accessibility. Crane placement (for tight lots) adds cost. Most California deliveries fall in the $2,000–$3,000 range.
Site Preparation: $3,000–$15,000
The widest range and most variable category. Foundation ($2,000–$8,000), utility connections ($5,000–$8,500 combined), grading and drainage (if needed: $2,000–$8,000). The single biggest variable: how close your utilities are to the ADU site.
Total Project Cost Ranges
Simple lot, minimal site work: $28,000–$36,000. Average California lot: $36,000–$40,000. Complex lot: $52,000–$54,000. Still a fraction of the $120,000–$200,000+ cost of a custom ADU build in California today.
FOR HOMEOWNERS
Browse All Blogs→
FREE PROPERTY EVALUATION
Find out if your lot qualifies for an ADU and what it could earn you.
Get My Free Evaluation →
USE CASES
Three reasons people add
a Kasita to their property.
Most customers come to us for one of these three things. Do any of these sound like you?
FOR HOMEOWNERS
Is a Backyard Office Worth It?
A Cost vs. Benefit Breakdown
Before you build a backyard office, you want to know if the numbers actually work. Here's an honest breakdown of what it costs
$1,800–$3,200/mo potential
FOR FAMILIES
From Booking to Move-In:
The 60-Day Kasita Timeline
60 days is achievable. Here is every phase from first site visit to move-in day — including where delays happen and how to avoid them.
From $22,000, no second mortgage
FOR REMOTE WORKERS
How Much Can You Earn Renting
a Backyard ADU in California?
The income potential from a backyard ADU varies by market, unit type, and rental strategy. Here are real numbers from California markets — and how to estimate what yours could earn.
From $21,500, adds property value
KASITA CRAFTERS
Build smart. Own more.
JOURNAL
ADU Guides
Build Stories
Permits & Zoning
Rental Income
PRODUCTS
Studio from $29,800
1-Bed from $22,000
2-Bed from $22,000
Office from $21,500
COMPANY
About Us
How It Works
Contact
Free Evaluation
© 2026 Kasita Crafters. California-based. All rights reserved.
Privacy
Terms