All plumbing within buildings or to premises served by the City water system shall be so installed and all plumbing fixtures so constructed and maintained as to prevent pollution or contamination of the City’s water supply, mains, lines and system by back siphonage or cross-connections. Water service to any premises or building known or found to have such defects and hazards shall be disconnected and not restored until such defects and hazards have been eliminated. (Ord. 4-1982 § 10, 1982.)