A dishwasher is an excellent addition to any kitchen, especially on those nights when washing dishes by hand would be a huge task. It is a lot easier to throw a large dinner party using dinnerware instead of plastic utensils when you know you're not going to spend hours cleaning up afterwards. If you own an older home and currently do not have a dishwasher, you can install one yourself. It requires only a little plumbing and muscle.
Turn off the power and water in your kitchen. Go to your circuit breaker and switch off power to the room. Look underneath your cabinets to locate the water lines and drainage pipe. Reach under the sink and turn off the water supply valve. If there is no valve, turn off the main water valve for the house. Turn on the kitchen faucet to drain the pipes.
Prepare to install your dishwasher. Measure to ensure the size of the opening in your cabinet fits the dishwasher. The standard width of dishwashers is 24 inches. The height of the dishwasher can be adjusted to fit the space. This is explained in Step 8.
Drill one hole in the back corner of the sink base cabinet, large enough for the drainage hose, supply tube, and power cord. (optional) This step is needed if your dishwasher is not next to the sink area and requires cords and tubing to be pulled through to the plumbing underneath the cabinet.
Connect the wiring and drainage. Take the faceplate off the base of dishwasher using a flathead screw driver. You should see an electrical box and the supply line inlet connection (this is where you attach your supply line in a later step) behind the faceplate when you remove it. All the wiring for the dishwasher is done here. Attach the drainage pipe to the water discharge pump. If building codes require your dishwasher to be vented using an air gap, mount the air gap in one of the sink holes using spring clamps. If you do not need an air gap, pull your drainage hose up in a loop to the top of the cabinet. Attach the hose to the wall with a strap (you can use an adjustable plastic strap). Looping the hose prevents a back flow from the sink.
Secure the drainage pipe to the garbage disposal (optional). Connect the drainage pipe to the garbage disposal inlet with a clamp. If there is a plug in the inlet, remove it. If you don't have a garbage disposal, instead of using the drainage pipe, use a dishwasher tailpiece for drainage by attaching it above the water trap underneath the sink (the drainage attached directly to the sink).
Connect your supply line. Connect one end of the supply line to the hot water pipe underneath your sink and the other end to the water inlet on the dishwasher using a right angle elbow piece. Tighten the supply line by hand, and then use a wrench to finish securing it. Wrap the ends of the elbow piece where the pipes join with Teflon tape to prevent leaks.
Wire the electrical box. Always double check to make sure the power is off. Pull the cable from the back of the electrical box on your dishwasher. Join the black wire (hot) and white wire (neutral) to the same coloured (corresponding) wires in the box in your wall using wire nuts. Wrap the ground wire from the wall box around the green screw located in the electrical box of the dishwasher. Use a screw driver to secure the screw on top of the wire. (Consult the owner's manual if the screw on your dishwasher is not green. It is the grounding screw.) Replace the cover on the electrical box.
Test the dishwasher to ensure it works properly. Let it complete one full cycle. If the cycle completes successfully, push your dishwasher into the cabinet. Adjust the height by heightening or lowering the feet underneath the dishwasher.
Complete the installation. Attach the dishwasher to the underside of your countertop with screws. Place the faceplate back on the front base of the dishwasher.
Make sure that you purchase the correct size supply lines and connecters before attempting to install your dishwasher.
Be prepared to spend a few hours on your hands and knees.