The operation by a city or town of a combined facility as provided for in RCW 35.67.331 shall be governed by the statutes relating to the establishment and maintenance of a city or town water system if the water system is one of the systems included in the combined acquisition, construction, or operation; otherwise the combined system shall be governed by the statutes relating to the establishment and maintenance of a city or town sewerage system.
RCW 35.67.340