The county handles building permits for all unincorporated areas, while incorporated cities like Yakima, Sunnyside, and Selah maintain their own independent building departments and permit processes. Development within the county is subject to critical areas ordinances, including flood hazard zones and irrigation district requirements for water rights.
How this fits with the state
The state authority here is Washington Department of Labor & Industries. The county file does not replace that — it adds the permit office, local overlays, and the actual filing path.