Back flow is defined as: “The undesirable reversal of flow of water or mixtures of water and other liquids, gases or other substances into the drinking water system. Occurs due to a pressure differential between two points within a continuous fluid system.” Back flow can occur where there is a cross connection between the public drinking water system and other pipes (like a sprinkler system), or other source of water, industrial fluid, gas or other substance, that can flow into the drinking water system as a result of pressure changes. (As a simple illustration, think of a siphon hose.)
The dangers of back flow is such that the State Division of Drinking Water has approved the following Rule to apply to Public Water Systems:
Rule 309-105-12: “[A] water supplier shall not allow a connection to his system which may jeopardize its quality and integrity. Cross connections are not allowed unless controlled by an approved and properly operating backflow assembly.
The prevention of “back flow” into the District’s culinary water is essential for the public’s health. This is why those with back flow assemblies on their sprinkling systems must have them inspected PRIOR to putting the systems into use for the summer season. This inspection must also be done by a Certified BackflowTechnician (a list is available at the District Office). Those property owners which we know to be subject to WCWID’s Cross Connection requirements will be receiving letters from the District informing them of their obligations.