Annexation is the process by which cities extend their municipal services, regulations, voting privileges, and taxing authority to a new area. One of the primary reasons for annexation is so that the city can regulate growth and development in a manner consistent with the city's vision. Annexation can preserve a growing urban area as a unified whole. It can also facilitate the full and efficient use of existing municipal resources.
Annexation boundaries are typically determined through a variety of factors including the ease of service delivery, the relationship to the existing city, whether there will be support from the property owners, that it is a logical growth pattern for the city, etc. There are several methods by which an annexation may be processed, the more common methods include:
60% Petition Annexation
The most frequently used method of annexing territory is by petition of property owners of at least 60 percent of the property value in the area (under RCW 35.13.125). This method is initiated by a property owner's written notice to city council announcing their intent to annex into the city.
The city council may initiate annexation proceedings by resolution (under RCW 35A.14.295) when there is an unincorporated area:
Containing less than 175 acres with all boundaries of the area contiguous to a code city; or
Of any size, containing residential property owners and having at least 80 percent of the boundaries contiguous to the city. The area must be within the same county and urban growth area designated under RCW 36.70A.110, and the city is required to plan under the Growth Management Act.
The city council may annex unincorporated territory, within the urban growth area (UGA), pursuant to a jointly approved interlocal agreement between the city and the county. Approval of such an agreement by special service districts such as fire protection districts, water-sewer districts and transportation benefit districts, within the proposed annexation area, is required.