It shall be unlawful for any person by himself, family, servants or agents to utilize the city water or sewage system without paying therefor, as herein provided or, without authority, to open any fire hydrant, stopcock, valve or other fixtures attached to the system of water supply unless it is done pursuant to proper application, agreement or resolution. It shall be unlawful to injure, deface or impair any part or appurtenance of the water or sewer system, or to cast anything into any reservoir or tank belonging to the water system. (1982 Code § 14-120)