Wash. Rev. Code § 35.85.020
Any such improvement may be initiated by the city council, or other legislative body, by a resolution, declaring its intention to order such improvement, which resolution shall set forth the nature and territorial extent of such proposed improvement, shall specify and describe the boundaries of the proposed improvement district and notify all persons who may desire to object thereto to appear and present such objections at a meeting of the council specified in such resolution and directing the board of public works, or other proper board, officer, or authority of the city, to submit to such council at or prior to the date fixed for such hearing the estimated cost and expense of the improvement, and a statement of the proportionate amount thereof which should be borne by the property within the proposed improvement district, and a statement of the aggregate assessed valuation of the real property exclusive of improvements, within said district, according to the valuation last placed upon it for purposes of general taxation. Such resolution shall be published in at least two consecutive issues of the official newspaper of the city, the date of the first publication to be at least thirty days prior to the date fixed by the resolution for hearing before the council.
Upon such hearing, or upon any adjournment thereof, the council shall have power to amend, change, extend, or contract the boundaries of the proposed improvement district as specified in the resolution, and to consider and determine all matters in relation to the proposed improvement, and, upon the conclusion of the hearing, or any adjournment thereof, shall have power by ordinance to order the improvement to be made and to adopt, fix and establish the boundaries of the improvement district. The action of such council in ordering such improvement, or in abandoning it, and in fixing and establishing the boundaries of the improvement district shall be final and conclusive. Any such ordinance may be passed upon majority vote of the council or other legislative body of the city.
Such ordinance may provide for the construction of the improvement in sections, the letting of separate contracts for each such section, and, in case the same is made in sections, separate assessment rolls to defray the cost and expense of any such section of such improvement may be prepared, and the amounts thereon appearing as finally determined, may be levied and assessed against real property within the improvement district. The provisions of law, charter and ordinance of any such city, relating to supplemental assessments, reassessments and omitted property shall be applicable to any improvement authorized in this chapter.
The city council, or other legislative body of such city, shall by general ordinance, make provision for hearing any objections in writing, to any assessment roll for such improvement, filed with the city clerk or comptroller at a prior date to the hearing thereon. Any right of appeal to the superior court provided by law to be taken from any local improvement assessment levied and assessed by any such city, may be exercised, within the time and in the manner therein provided, by any person so objecting to any assessment levied and assessed for any improvement authorized in this chapter.
RCW 35.85.020
Appeal from local improvement district assessments: RCW 35.44.200 through 35.44.270.