PDFWAC 246-215-05275
Operation and maintenance—Prohibiting a cross connection (FDA Food Code 5-205.12).
(1) A person may not create a cross connection by connecting a pipe or conduit between the drinking water system and a nondrinking water system or a water system of unknown quality.
(2) The piping of a nondrinking water system must be durably identified so that it is readily distinguishable from piping that carries drinking water.