All definitions contained in the Idaho Regulations for Public Drinking Water, as the same may hereafter be revised or amended, shall be considered as definitions within the meaning of this Chapter, and the following terms shall have the meanings ascribed to them in this Section:
BACKFLOW: The flow, other than the intended direction of the flow, of any foreign liquids, gases or substances into this district's public water supply distribution system.
BACKFLOW PREVENTION DEVICE: A device to counteract back pressure or to prevent back siphonage.
CONTAMINATION: The entry into or the presence into the City water supply of any substance which may be detrimental to health and/or quality of water.
CROSS-CONNECTION: Any physical arrangement whereby a public water supply is connected, directly or indirectly, with any other water supply system, sewer, drain, conduit, pool, storage reservoir, plumbing fixture, or other device which contains or may contain contaminated water, sewage or other waste or liquids of unknown or unsafe quality which may be capable of imparting contamination to the public water supply system of the City as a result of backflow. (1980 Code § 8.4.2)