Can I Build ADU in Spokane, WA? (2026)
Find out if you can build a adu in Spokane, WA. Rules, permit requirements, costs, and next steps.
Yes, ADUs are allowed in Spokane, WA. California state law ensures by-right approval.
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a residential lot — also called a granny flat, in-law suite, or backyard cottage. In Spokane, WA, ADUs are permitted by right under state law, making them one of the most accessible ways to add housing on your property. ADUs can be detached, attached to the main home, or created by converting an existing garage or accessory structure.
ADU Rules in Spokane
ADU Rules in Spokane: Detached ADU max size: 1000 sq ft. Attached ADU max size: 1000. Setbacks: 5 ft side, 5 ft rear. Owner-occupancy: No owner-occupancy requirement per Washington HB 1337, which explicitly removes owner-occupancy requirements statewide. Property owners do not need to reside on the property.. State preemption applies: WA law requires Spokane to approve compliant ADUs by right.
Costs & Fees
ADU permits in Spokane: Total estimated permit cost: $1,000–$5,000 total fees. Contact the City of Spokane Building Services for current fee schedule.
Timeline
Spokane Planning Department: plan review typically 3-6 weeks. Spokane has implemented expedited ADU review to comply with HB 1337. Construction 4-10 months.
Next Steps
Next steps for building an ADU in Spokane: 1. Review full ADU rules including size limits, setbacks, and parking. 2. Apply for an ADU permit through the City of Spokane Building Services at https://my.spokanecity.org/buildingservices/permits/. 3. Hire a licensed contractor familiar with WA ADU requirements.
City of Spokane Building Services
Phone: (509) 625-6300
Website: https://my.spokanecity.org/buildingservices/
Online Permits: https://my.spokanecity.org/buildingservices/permits/
Frequently Asked Questions
Can I build an ADU on my Spokane property?
Yes. Washington HB 1337 (2023) requires Spokane to allow at least 2 ADUs per single-family lot by-right, without owner-occupancy requirements. ADUs are limited to 1,000 sqft. No owner-occupancy requirement. Spokane has updated its Municipal Code to comply with state law. The permit must be processed ministerially. Contact Spokane Planning or Building Services for specific requirements.
How is Spokane different from Seattle?
Spokane and Seattle are both major Washington cities but are very different places. Spokane is in Eastern Washington, 280 miles east of Seattle across the Cascade Mountains, which create a rain shadow making Spokane dry and semi-arid. Seattle receives 37 inches of rainfall per year; Spokane gets 17 inches but 50 inches of snow. Seattle's median home price is roughly double Spokane's. Avista Utilities serves Spokane's electric and gas needs — completely different from Seattle City Light or Puget Sound Energy. Spokane's economy is driven by healthcare, education, and government rather than tech.
Who provides electricity in Spokane?
Avista Utilities provides both electric and natural gas service to Spokane. This is different from most of Western Washington, which is served by Puget Sound Energy or municipal utilities like Seattle City Light. Avista is a regulated investor-owned utility headquartered in Spokane. For solar installations, you'll need both a permit from Spokane Building Services and an interconnection agreement with Avista.
Are short-term rentals allowed in Spokane?
Yes. Short-term rentals are allowed in Spokane with a license ($150/year). Spokane's STR market benefits from tourism (outdoor recreation, Gonzaga athletics, conventions at the Convention Center), university visitors (Gonzaga, Eastern Washington University, WSU Medical School), and sports tourism (Hoopfest, Bloomsday). Washington State Hotel-Motel Tax and Spokane lodging taxes apply to all STR rentals.
Is solar worth it in Spokane compared to Seattle?
Solar is actually more productive in Spokane than Seattle due to Eastern Washington's drier, sunnier climate. Spokane has approximately 25 more sunny days per year than Seattle. While Spokane's electricity rates may be lower than Seattle (reducing the dollar value of each kWh), the higher solar production can offset this. Avista offers net metering. Washington State's sales tax exemption on solar equipment applies throughout the state. A solar installer can provide a site-specific production estimate.
Source: City of Spokane Building Services — Building Regulations. Last verified April 6, 2026. View source