All revenue derived from the sale of water as herein provided shall be kept separate and apart by the Treasurer of the City from the other revenue of the City, and said monies shall be known as the Water Fund and shall be used exclusively for Water and Sewer Department purposes; that is for the maintenance, extension, improvement and operation of said Water and Sewer Department, the retirement of the Water and Sewer Department bonds, certificates, etc., and under no circumstances shall this revenue be diverted to any other purpose, unless voted on by City Council. (1994 Code)