Looking for accessory dwelling unit companies in Spokane, WA? Call AccessoryDwellingUnit Services for a contact a provider — no obligation. Licensed adu builders serve Spokane and the surrounding area, and you'll get straight answers on timing and what affects the price.

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

These companies provide comprehensive support for homeowners, often pairing design experts with construction crews to handle the entire project under one roof. They are helpful when you want to avoid hiring separate architects and builders. You should look into these companies when you want a streamlined experience and a single point of accountability for your backyard project from start to finish.

Frequently asked in Spokane

What are the disadvantages of ADUs in Spokane?

How much does an ADU cost in Washington?

What are the rules for ADUs in Washington State?

Washington State has specific regulations regarding ADU size, setbacks, and permitting, which apply to Spokane. Local Spokane ordinances may also add further requirements. Understanding these rules is crucial for a smooth project.

Is an ADU allowed in Washington?

Yes, accessory dwelling units are allowed in Washington State, including in Spokane. State law provides a framework, and cities like Spokane have their own specific zoning codes and approval processes to follow.

That specific grant is for California and doesn't apply to Washington State or Spokane. However, there might be local incentives or financing options available for ADUs in Spokane that a consultation can explore.

Can I build an ADU on my property in Spokane?

Generally, yes, many properties in Spokane are zoned to allow ADUs. The specific rules depend on your lot size, existing structures, and adherence to Spokane’s land use regulations. We can help you find out for sure.

Also serving nearby: Spokane Valley · Yakima · Bellevue · Renton · Kirkland

All cities in Washington →

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

Service area details

229,447residents

3,336per sq mile

8ZIP codes served

Serving all of Spokane — population 229,447; about 3,336 residents per square mile across 68.8 sq mi. ZIP codes covered include 99201, 99202, 99203, 99204, 99205, 99206, 99207, 99208.

Neighborhoods served in Spokane: Browne's Addition, South Hill, Northwest Spokane, West Spokane, East Spokane — and every surrounding area.