Wash. Rev. Code § 35A.14.299
Such annexation ordinance as provided for in RCW 35A.14.297 shall be subject to referendum for forty-five days after the passage thereof. Upon the filing of a timely and sufficient referendum petition with the legislative body, signed by qualified electors in number equal to not less than ten percent of the votes cast in the last general state election in the area to be annexed, the question of annexation shall be submitted to the voters of such area in a general election if one is to be held within ninety days or at a special election called for that purpose according to RCW 29A.04.330. Notice of such election shall be given as provided in RCW 35A.14.070 and the election shall be conducted as provided in RCW 35A.29.151. The annexation shall be deemed approved by the voters unless a majority of the votes cast on the proposition are in opposition thereto.
After the expiration of the forty-fifth day from but excluding the date of passage of the annexation ordinance, if no timely and sufficient referendum petition has been filed, the area annexed shall become a part of the code city upon the date fixed in the ordinance of annexation. From and after such date, if the ordinance so provided, property in the annexed area shall be subject to the proposed zoning regulation prepared and filed for such area as provided in RCW 35A.14.330 and 35A.14.340. If the ordinance so provided, all property within the area annexed shall be assessed and taxed at the same rate and on the same basis as the property of such annexing code city is assessed and taxed to pay for any then outstanding indebtedness of such city contracted prior to, or existing at, the date of annexation.
RCW 35A.14.299
Effective date-2006 c 344 ss 1-16 and 18-40: See note following RCW 29A.04.311.