A "cross-connection" is any actual or potential physical connection between a public water system or the consumer's water system and any source of non-potable liquid solid, or gas that could contaminate the potable water supply by backflow. "Backflow" means the undesirable reversal of flow of water or other substances through a cross-connection into the public water system or consumer's potable water system. An Irrigation system is an example of a low hazard cross-connection. An example of a high hazard cross-connection would be a garden hose with the flowing end submerged in a container of pesticide. For more information please contact the Public Works Department at 425-831-4919.