RCW 35.58.050
RCW 35.58.050: Functions authorized.
A metropolitan municipal corporation shall have the power to perform any one or more of the following functions, when authorized in the manner provided in this chapter: (1) Metropolitan water pollution abatement. (2) Metropolitan water supply. (3) Metropolitan public transportation. (4) Metropolitan garbage disposal. (5) Metropolitan parks and parkways. (6) Metropolitan comprehensive planning.