Spokane ADU Zoning Rules & Permit Guide

ADU Regulations in Spokane, Washington

Updated September 29, 2026

Eastern Washington's largest city, Spokane permits ADUs under Washington's HB 1337 which limits local restrictions. Spokane's municipal code requires owner occupancy and prohibits short-term rental use of ADUs, preserving them for long-term housing.

Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in Spokane as of 2026. Regulations are governed by Washington's HB 1337 (2023) which limits local ADU restrictions statewide.

Additional Local Requirements for Spokane

• Maximum lot coverage: 35%
• ADU must be at least 200 sq ft
• Property owner must occupy primary residence
• Short-term rental of ADU prohibited
• WA HB 1337 limits local restrictions

Frequently Asked Questions About ADUs in Spokane

Can I build an ADU in Spokane?

Spokane allows ADUs in single-family and multi-family zones. Owner occupancy is required and the ADU cannot be used as a short-term rental.

What is the maximum ADU size allowed in Spokane?

ADUs in Spokane can be up to 1,000 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the Spokane planning department before designing your project.

What are the setback requirements for an ADU in Spokane?

ADUs in Spokane generally require setbacks of 5 ft rear, 5 ft side. Washington's HB 1337 (2023) limits how restrictive local ADU rules can be, but the exact setback figures come from Spokane's own land use code — confirm them with the city before you design.