: I just installed a new dishwasher. The location is not adjacent to the sink so it was not convenient to connect supply and drain to the sink connections. I ran the supply line through the floor to a hot water supply directly below in the cellar. I also ran the drain through the floor to the septic drain. I installed a trap just below the floor level between the washer and the septic drain. My question is this: The instructions say that when connecting the dishwasher drain to the sink drain a loop must be provided in the drain pipe that is about as high as the dishwasher. Why is a loop necessary? I obviously have no loop. Do I need a loop as high as the dishwasher even though I am not going into the sink drain? Thanks