Wash. Rev. Code § 35.13A.111
The board of commissioners of a water-sewer district, with fewer than two hundred fifty customers on July 24, 2005, and the city council of a code city with a population greater than one hundred thousand on July 24, 2005, may provide for assumption by the city of the district in accordance with RCW 35.13A.020, except as provided herein, pursuant to the terms and conditions of a contract executed in accordance with RCW 35.13A.070. None of the territory of the water-sewer district need be included within the territory of the city. The contract and assumption shall be approved by resolution of the board of commissioners and ordinance of the city council. If the water-sewer district has no indebtedness or monetary obligations on the date of assumption, the city shall use any surplus funds only for water services delivered to and water facilities constructed in the former territory of the district, unless provided otherwise in the contract. In connection with the assumption, the water-sewer district or the city, or both, may provide for dissolution of the district pursuant to RCW 35.13A.080.
RCW 35.13A.111