Sep 04, 2014 · Camco RV Quickie Flush with Back Flow Preventer helps to thoroughly flush the holding tank without bringing a hose through the window. A permanently installed built-in backflow preventer helps to keep sewage from contaminating water line. Hook garden hose to the connection (outside RV) and flush for 2 minutes or until water runs clear.
When you flush—usually by a foot pump or an electric flush—the contents of the bowl go into the sealed-off black water tank. The tank is plumbed to the side of the RV and connects to a hose, which is used to drain the tank into a dump point.