A dishwasher drain hose connects to the water pump on the bottom of the appliance and to the sink drain at the garbage disposal, sink drain pipe or air gap. First-time installation of a dishwasher requires the replacement of pipe to provide a connection point for the drain hose.
When a garbage disposal exists in the sink plumbing, it is the preferred installation point for a dishwasher drain hose. An air gap is a device that prevents the back-flow of water from the drain pipe into the dishwasher. In the absence of an air gap, the dishwasher hose connects directly to a stem in the drain pipe.