(1) The legislative body of a county, city, or town planning under chapter 36.70A RCW and subject to the requirements of RCW 36.70A.215 may initiate an annexation process for unincorporated territory by adopting a resolution commencing negotiations for an interlocal agreement as provided in chapter 39.34 RCW between a county and any city or town within the county. The territory proposed for annexation must meet the following criteria: (a) Be within the city or town urban growth area designated under RCW 36.70A.110, and (b) at least 60 percent of the boundaries of the territory proposed for annexation must be contiguous to the annexing city or town or one or more cities or towns.

(2) If the territory proposed for annexation has been designated in an adopted county comprehensive plan as part of an urban growth area, urban service area, or potential annexation area for a specific city or town, or if the urban growth area territory proposed for annexation has been designated in a written agreement between a city or town and a county for annexation to a specific city or town, the designation or designations shall receive full consideration before a city or county may initiate the annexation process provided for in RCW 35.13.480.

(3) The agreement shall describe the boundaries of the territory to be annexed. A public hearing shall be held by each legislative body, separately or jointly, before the agreement is executed. Each legislative body holding a public hearing shall, separately or jointly, publish the agreement at least once a week for two weeks before the date of the hearing in one or more newspapers of general circulation within the territory proposed for annexation.

(4) If an interlocal agreement under this section is used for a sales and use tax under RCW 82.14.415, the agreement under this section must address the following:

(a) Balancing of annexations of commercial, industrial, and residential properties so that any potential loss or gain is considered and distributed fairly as determined by tax revenue;

(b) Development, ownership, and maintenance of infrastructure; and

(c) The potential for revenue-sharing agreements.

(5) Following adoption and execution of the agreement by both legislative bodies, the city or town legislative body shall adopt an ordinance providing for the annexation of the territory described in the agreement. The legislative body shall cause notice of the proposed effective date of the annexation, together with a description of the property to be annexed, to be published at least once each week for two weeks subsequent to passage of the ordinance, in one or more newspapers of general circulation within the city and in one or more newspapers of general circulation within the territory to be annexed. If the annexation ordinance provides for assumption of indebtedness or adoption of a proposed zoning regulation, the notice shall include a statement of the requirements. Any territory to be annexed through an ordinance adopted under this section is annexed and becomes a part of the city or town upon the date fixed in the ordinance of annexation, which date may not be fewer than 45 days after adoption of the ordinance.