ADUs · California

ADUs Costs in California — Expected Price Range & Breakdown

In California, most adu projects cost between $50,000 and $200,000 per job, with a typical price near $100,000. Local labour, permits and materials move the final price, so treat the range below as a planning guide.

Typical adu cost

$50,000 – $200,000

per job · typical $100,000

A general planning range, not a quotation.

Adu cost breakdown

  • Garage conversion$30,000 – $80,000typical $50,000
  • Attached ADU (addition)$80,000 – $200,000typical $120,000
  • Detached ADU (new build)$100,000 – $300,000typical $180,000

At a glance

  • Typical range$50,000 – $200,000
  • Unitper job
  • Cities covered200

What ADUs costs

Costs cover design, permits, construction, and utilities for adding a separate living unit on your property. Detached units are pricier than attached or garage conversions. Local regulations and site conditions significantly affect price.

By city in California

Frequently asked questions

How much does an ADU cost on average?
Nationally, $100,000–$200,000 for a typical 600-1,200 sq ft unit. Garage conversions may cost less, while high-end detached units exceed $250,000.
What drives ADU costs?
Size, type (attached/detached), foundation, plumbing/electrical runs, and local permit fees. Site conditions like sloping land or need for a new sewer line increase costs.
How can I save on ADU construction?
Use prefabricated units, convert existing space, shop for contractors, and finance with a HELOC or construction loan. Check for local grants or incentives for ADUs.