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.
Frequently asked in Federal Way
What is an ADU unit in Federal Way?
An ADU unit in Federal Way is a secondary housing space on a residential property, separate from the main house. It's designed to be fully self-sufficient with its own kitchen, bathroom, and living area. These units can be attached to your existing home, built as a detached structure in your backyard, or even created by converting an existing space like a garage. ADUs offer flexible solutions for homeowners in Federal Way, whether for family, guests, or rental income.
How do I get an ADU estimate in Federal Way?
What makes an accessory dwelling unit a good choice in Federal Way?
An accessory dwelling unit can be a great choice for Federal Way homeowners looking to increase their property's value and utility. It provides opportunities for rental income, extra space for family members, or a dedicated home office. ADUs are a cost-effective way to expand living space without the need to move. They can also offer greater privacy and independence for occupants compared to living within the main house. Many in Federal Way find them a practical solution.
Are accessory dwelling unit builders near me in Federal Way?
What are homes with in-law suites like in Federal Way?
Homes with in-law suites in Federal Way are designed to provide a comfortable, private living space for extended family or guests. These suites typically include a bedroom, a bathroom, and often a small kitchen or kitchenette. They can be attached to the main house, like a basement apartment, or exist as a separate dwelling on the property. These suites are ideal for multigenerational living, offering independence while keeping loved ones close. They add significant value and functionality to Federal Way homes.
What is the permit cost for an ADU in Federal Way?
What is the process for ADU construction 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: Kew Gardens, The Lakes, West Campus, Woodcreek, Chase Lake — and every surrounding area.
Areas we serve
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