Powers conferred by chapter are supplemental.
(1) The powers and authority conferred by this chapter are supplemental to powers and authority conferred by other law, and nothing contained in this chapter may be construed as limiting any other powers or authority of any municipal corporation or other entity under applicable law.
(2) As to water companies that are regulated by the utilities and transportation commission under Title
80 RCW, nothing in this chapter is intended to change or limit the authority or jurisdiction of the utilities and transportation commission.