King County, WA Home Business: Home Occupation Permits (2026)

Unlike some jurisdictions, King County does not issue a dedicated home occupation permit for home businesses in unincorporated areas. Instead, any home business that meets the accessory use standards in KCC 21A.30.080 — including operation by residents only, no more than one non-resident employee, no outdoor storage, no impacts beyond the property line, and no prohibited uses — is considered a permitted accessory use by right. Home occupations that exceed these standards, or that fall into certain categories (larger scale, unusual traffic, or uses requiring specific review), may need a conditional use permit through the King County Department of Local Services Permitting Division. All home-based businesses in Washington State must register with the Washington State Department of Revenue Business Licensing Service, obtain a Unified Business Identifier (UBI), and file for state Business and Occupation (B&O) tax. A local King County business license endorsement may be required depending on the type of business. Businesses that will have walk-in clients or specific health and safety concerns may need additional permits, such as food handler permits (Public Health Seattle and King County), cosmetology licenses (Washington Department of Licensing), or specific trade licenses. Home daycare, cottage food, and certain other uses trigger additional state-level permits as described in those subcategories. If the home business involves any building alterations (converting a garage to a workshop, adding a home office), building and electrical permits may be required through the Department of Local Services.