How to Install a Dishwasher
With the right connections and cables, you can install a dishwasher in just five steps.
Once you have the site prepared, installing a dishwasher is easy. The hardest part is determining if you have all of the necessary hookups. After all, three connections are needed for a dishwasher: an electrical cable supplying 120 volts of power; a drain line running to the trap or garbage disposer; and a supply line, hooked to a stop valve under the sink, that brings water to the dishwasher.
Once you have the connections in place, make the opening the correct size and test-fit the dishwasher. The cabinets on either side should be spaced according to manufacturer's instructions—usually 24-1/4 inches.
Then run an electrical cable—armored or nonmetallic, as required by code—to the space. Make sure it will not bump into the dishwasher's frame. A 14/2 cable is adequate for a 15-amp circuit. Make sure the dishwasher will not overload the circuit. Hire an electrician if you are unsure.
Most dishwashers come with a drain hose. The drain hose runs to an air gap mounted to a knockout hole in the sink. From there, another length of hose runs to the garbage disposer. If there is no garbage disposer, the hose runs to a dishwasher tailpiece on the trap. The water supply line is typically flexible copper, connected to its own shutoff valve.
You'll need about an hour to install the dishwasher once the electrical and plumbing lines are run and the cabinets are installed.
What You Need
- Tubing cutter
- Adjustable wrench
- Wire strippers
- Groove-joint pliers
- Dishwasher with drain hose
- Flexible copper supply line
- Hose clamps
- Air gap
- Electrical cable
- Wire nuts
Step 1: Trim Water Supply Line
Using a tubing cutter trim the water supply line to the necessary length. Make sure the electrical cable is long enough to reach the junction box built into the dishwasher.
Step 2: Push Dishwasher In
Push the dishwasher into the opening. As you do so, thread the drain hose through the 1-1/2 -inch hole already cut in the cabinet. Make sure the lines do not become kinked or bent.
Step 3: Add and Tighten Nut
Slip a nut and ferrule onto the end of the supply line. Carefully bend the tubing and insert it into the dishwasher's supply inlet. Slide the ferrule down into the inlet and tighten the nut. Open the stop valve and check for leaks; you may need to tighten the nut further.
Step 4: Run Drain Line
Run the drain line to the air gap, then to the garbage disposer or a tailpiece with a special dishwasher drain fitting. Slide a hose clamp onto the hose, slip the hose onto the fitting, slide the clamp over the fitting, and tighten the clamp.
Step 5: Run Electrical
Run the electrical cable through the cable clamp and tighten the clamp nuts to hold the cable firm. Strip and splice wires—black to black, white to white, and ground (green or copper) to ground. Cap each splice with a wire nut and install the electrical cover plate.
Bonus: How to Anchor and Level the Dishwasher
Slide the dishwasher in far enough so that only its decorative trim is visible. If the dishwasher won't go in far enough, pull it out and look for obstructions.
Stand back and check that the dishwasher looks straight in relation to the cabinets and the countertop. To raise or lower one or both sides, use groove-joint pliers to turn the feet at the bottom of the unit. Wiggle the dishwasher to test that it rests solidly on all four feet.
Once satisfied with the dishwasher's position, open the door and find the mounting tabs (usually on the top edge, sometimes on the sides). Drill pilot holes. To avoid drilling up through the countertop, wrap a piece of tape on the drill bit to mark the depth at which to stop. Drive short screws into the holes to anchor the dishwasher to the countertop.