Wash. Rev. Code § 35.95.040
The corporate authorities of a municipality are authorized to adopt ordinances for the levy and collection of excise taxes and/or for the imposition of an additional tax for the act or privilege of engaging in business activities. Such business and occupation tax shall be imposed in such amounts as fixed and determined by the corporate authorities of the municipality and shall be measured by the application of rates against value of products, gross proceeds of sales, or gross income of the business, as the case may be. The terms "business", "engaging in business", "gross proceeds of sales", and "gross income of the business" shall for the purpose of this chapter have the same meanings as defined and set forth in chapter 82.04 RCW or as said chapter may hereafter be amended.
The excise taxes other than the business and occupation tax above provided for shall be levied and collected from all persons within the municipality in such amounts as shall be fixed and determined by the corporate authorities of the municipality: PROVIDED, That such excise tax shall not exceed one dollar per month for each housing unit. For the purposes of this section, the term "housing unit" shall mean a building or portion thereof designed for or used as the residence or living quarters of one or more persons living together, or of one family.
All taxes herein authorized shall be taxes other than a retail sales tax defined in chapter 82.08 RCW and a use tax defined in chapter 82.12 RCW, and the municipality shall appropriate and use the proceeds derived from all taxes authorized herein only for the operation, maintenance and capital needs of its municipally owned or leased and municipally operated public transportation system.
Before any county transportation authority established pursuant to chapter 36.57 RCW or any public transportation benefit area authority established pursuant to chapter 36.57A RCW may impose any of the excise taxes authorized pursuant to this section, the authorization for imposition of such taxes shall be approved by the voters residing within such respective area.
The county on behalf of an unincorporated transportation benefit area established pursuant to RCW 36.57.100 and 36.57.110 may impose any of the excise taxes authorized pursuant to this section only within the boundaries of such unincorporated transportation benefit area.
RCW 35.95.040
Severability-Effective date-1975 1st ex.s. c 270: See notes following RCW 35.58.272.
Municipal taxation of motor carriers of freight for hire: RCW 35.21.840.