Before undertaking any dishwasher installation work, first turn off both electricity and water supplies at your breaker box or shut-off valve in the kitchen. Carefully tilt back the machine on its backside while simultaneously taking steps to unbolt its front access panel and remove.
Connect the dishwasher’s water supply line (usually flexible copper or braided stainless steel tubing) to its 90-degree fitting on the back.
1. Make Sure It’s Level
Tip your dishwasher over on its back to make electrical connections more accessible. Unscrew any screws securing the kickplate and pull it off before feeding three exposed wires from the power cord into a round opening in the junction box – typically attached at its base – of which there should be three exposed.
Check the leveling feet at the rear of your dishwasher to make sure it is level front to back. If not, loosen any mounting nuts with pliers or an adjustable wrench and readjust feet until bubble in your level is centered.
Reconnect the power cord and drain hose to your dishwasher, following your product manual’s instructions to connect the water supply line and activate its shutoff valve.
2. Install the Drain Hose
No matter if or when using an air gap dishwasher, a high loop must be added in your drain line in order to prevent wastewater from the sink drain or garbage disposal from siphoning back into the machine during a drain cycle.
Start by disconnecting the old hose from its connection under the sink (this could either be an air gap or sink drain tailpiece), which may be held together with a stainless steel worm clamp or spring clip that you can loosen using pliers or a screw driver.
Connect the new hose to the small side of the air gap, then the Y-branch tailpiece on either your sink drain itself (if using an air gap) or to its small side ( if not). Secure each end with a hose clamp.
3. Connect the Water Line
Use either the drain line connection on your garbage disposal or a water supply line running from an under-sink water shutoff valve directly to your dishwasher for this step. If using this latter approach, first turn off all electricity at the circuit breaker before shutting off water supply by turning valve counterclockwise on existing pipe.
Your dishwasher likely came equipped with a small, 90-degree fitting at the back that connects to a supply line; here you will connect the supply line. Flexible copper or braided stainless steel lines with matching fittings can be purchased from hardware stores for this purpose.
Next, place the dishwasher on its side on cardboard or a towel in order to prevent scratches in your flooring while you work.
4. Connect the Power Cord
Sometimes dishwashers are wired via plug and cord instead of hard wiring them directly, in which case you must first disconnect both power cord and sheathed water supply line by loosening cable clamp and pulling free (Photo 1). You will require new electrical line and cord, labeled specifically for appliances with three prong plug.
Unplug and turn off water supply valve. Remove kickplate to gain access to terminal box. Unscrew cover of terminal box, feed three exposed wires from power cord through opening in terminal box using wire nuts; connect black and white wires using another wire nut, with green grounding wire going directly to a screw or fixture’s grounding screw in terminal box, replacing and securing cover when completed.
5. Connect the Drain Line
Once your dishwasher is set and level, begin threading its drain line, water supply line and power cord through holes drilled in its cabinet for them. Before doing this, however, be sure to consult with your manufacturer so the proper connections are made.
If your dishwasher will be connected to a garbage disposal, add an air gap (see video above) before connecting it to the P-trap to prevent sewage gasses from seeping into the kitchen and creating unpleasant odors.
If using an existing dishwasher hose, secure it to the valve port by hand-tightening before tightening a 1/4 turn further using pliers. For an alternate approach, try connecting the supply tube directly to the valve port via its 90-degree elbow fitting and then screwing on a dual outlet shutoff valve.