At each premises where the city deems necessary, a user supervisor shall be designated by, and at the expense of, the water user. This user supervisor shall be responsible for monitoring backflow prevention devices and for avoiding cross connections. The user supervisor shall promptly notify the city in the event of contamination or pollution of the public water system due to a cross connection on the premises. Such notice will allow the city to take appropriate measures to mitigate the contamination. The water user shall inform the city annually of the user supervisor's identity and whenever a change in user supervisors occurs. (1988 Code)