In this video, This Old House plumbing and heating expert Richard Trethewey teaches you how to replace a dishwasher drain hose.
1. Use pliers to disconnect the dishwasher's discharge hose from the T-fitting underneath the kitchen sink.
2. From inside the sink cabinet, tape a new discharge hose to the end of the old discharge hose.
3. Reach underneath the dishwasher and pull the old discharge hose and new hose into the space beneath the dishwasher.
4. Remove the tape holding together the two discharges hoses and drain water from the old hose into a shallow baking dish.
5. Use a nut driver to disconnect the opposite end of the old discharge hose from the dishwasher.
6. Attach the new discharge hose to the discharge port on the dishwasher. Secure the hose end with a stainless-steel hose clamp. Tighten the clamp with a nut driver.
7. From inside the sink cabinet, run the discharge up as high as possible, forming an arcing loop. Secure the hose to the inside of the cabinet with screw-on metal clamps.
8. Connect the end of the new discharge hose to the dishwasher T-fitting on the sink's drainpipe.
9. Run the dishwasher three or four times with hot water, but no dishes, to flush out the sump and discharge hose.