Wash. Rev. Code § 36.120.170
Within thirty days of the completion of the construction of the transportation project or series of projects forming the regional transportation investment plan, the district shall terminate day-to-day operations and exist solely as a limited entity that oversees the collection of revenue and the payment of debt service or financing still in effect, if any. The district shall accordingly adjust downward its employees, administration, and overhead expenses. Any taxes, fees, or tolls imposed under an approved plan terminate when the financing or debt service on the transportation project or series of transportation projects constructed is completed and paid, thirty days from which point the district shall dissolve itself and cease to exist. If there is no debt outstanding, then the district shall dissolve within thirty days from completion of construction of the transportation project or series of transportation projects forming the regional transportation investment plan. Notice of dissolution must be published in newspapers of general circulation within the district at least three times in a period of thirty days. Creditors must file claims for payment of claims due within thirty days of the last published notice or the claim is extinguished.
RCW 36.120.170