Wash. Rev. Code § 67.30.020
The counties and cities are authorized, upon passage of an ordinance in the prescribed manner, to participate in the financing, construction, acquisition, operation, and maintenance of multipurpose sports stadia within their boundaries. Counties and cities are also authorized, through their governing authorities, to purchase, lease, condemn, or otherwise acquire property, real or personal; to construct, improve, maintain and equip buildings or other structures; and expend moneys for investigations, planning, operations, and maintenance necessary for such participation.
The cost of any such acquisition, condemnation, construction, improvement, maintenance, equipping, investigations, planning, operation, or maintenance necessary for such participation may be paid for by appropriation of moneys available therefor, gifts, or wholly or partly from the proceeds of revenue bonds as the governing authority may determine.
RCW 67.30.020