Adu quote — Federal Way, WA
Last updated: September 24, 2026
What affects the price
Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.
About this service
An ADU quote is a detailed breakdown of the costs to build your secondary unit, including site preparation, materials, and labor. Factors like foundation type, utility trenching distance, and interior finish levels will move your total up or down. It provides the financial roadmap for your project. Exact pricing confirmed free on the call.
Frequently asked in Federal Way
What's involved in finding an accessory dwelling unit contractor in Federal Way?
How do I find accessory dwelling units near me in Federal Way?
What are the options for a detached accessory dwelling unit in Federal Way?
What local ADU services are available in Federal Way?
What is the cost to build an accessory dwelling unit in Federal Way?
Can I get an ADU estimate in Federal Way?
What are accessory dwelling unit grants in Federal Way?
Also serving nearby: Tacoma · Kent · Renton · Seattle · Bellevue
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Federal Way — population 97,701; about 4,375 residents per square mile across 22.3 sq mi. ZIP codes covered include 98003, 98023, 98063, 98093.
Neighborhoods served in Federal Way: The Lakes, Mirror Lake, Woodmont, Star Lake, Twin Lakes — and every surrounding area.
Areas we serve
Browse by state, then city.