Adu quote — Seattle, WA

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

About this service

An ADU quote is a detailed breakdown of the costs to build your specific project after we have reviewed your site and design choices. Factors like soil conditions, utility connections, and your choice of finishes will influence the final number. We provide a clear, line-item document so you know exactly where your money is going. Exact pricing confirmed free on the call.

Frequently asked in Seattle

Also serving nearby: Kirkland · Bellevue · Renton · Kent · Federal Way

All cities in Washington →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Seattle — population 755,078; about 8,989 residents per square mile across 84.0 sq mi. ZIP codes covered include 98101, 98102, 98103, 98104, 98105, 98106, 98107, 98108.

Neighborhoods served in Seattle: Queen Anne, Ballard, Fremont, West Seattle, Green Lake — and every surrounding area.