How to install a dishwasher under a granite countertop

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When it’s time for you to buy a dishwasher, granite countertops may affect what you’re able to install. Most dishwashers mount to the bottom of the kitchen countertop so the dishwasher doesn’t fall forward when you open the door. However, you can’t screw into the underside of a granite countertop because it could damage your granite. During your dishwasher installation, granite countertops will require you to change up your technique a bit, but it’s worth it to enjoy the convenience of a dishwasher and the beauty of granite in your kitchen.

Turn off the water supply to your house.

Remove the access panel on the bottom of your dishwasher to access the power cord connection, drain outlet and inlet solenoid valve.

Slide the dishwasher into its designated location and note the location of your cords so you know where to drill.

Cut a 1½-inch hole in the sink cabinet wall to run these cords through. Use a power drill with a hole saw attachment to make this hole.

Run the drain outlet, inlet solenoid valve and power cord through the hole so the cords are underneath your kitchen sink. Slide your dishwasher into place so you can fully pull the cords through the hole.

Install a compression elbow on the inlet solenoid valve, and then bend your supply line so it lines up with the compression elbow. Slide a compression nut over your tubing, and then put a compression ring on the end. Use an adjustable wrench to connect the tubing to the inlet solenoid valve. Turn on the water and inspect your tubing for leaks.

Level the dishwasher. Open and close the dishwasher door and adjust the threaded front feet as necessary so the dishwasher sits level. It should open without bumping the countertop or the side cabinets. When the door remains open, it should sit flat, not slanted to one side or the other. Tighten the locknuts on the threaded feet once the dishwasher sits level.

Secure the dishwasher to your countertop. Check with the dishwasher manufacturer for an alternate mounting kit to help secure the dishwasher in place. Because you can’t secure the dishwasher to the granite countertop since the screws won’t penetrate granite without causing damage, manufacturers may offer an alternative so you can secure the dishwasher and it won’t tip over.

Attach a wooden strip underneath your countertop if an alternate mounting kit isn’t available when you install the dishwasher. Granite won’t allow you to secure the dishwasher directly to the countertop, but you can secure the dishwasher to this wooden strip. Use construction adhesive to secure the wooden strip to the countertop, and then drill through the dishwasher brackets into the wooden strip to secure the dishwasher to the countertop.

Install a new drain tailpiece under the sink with a piece that has a side inlet. Use hose clamps to connect the dishwasher’s drain line to the dishwasher outlet. Use another hose clamp to connect a hose from the dishwasher to the side inlet on your new kitchen sink pipe.

Connect the wiring from your dishwasher’s power cord to your power supply. Use wire nuts to connect the white wire to the white wire, the black wire to the black wire and the green wire to the ground screw. Plug your cord into the electrical socket underneath the sink.

Turn your dishwasher on to run a test cycle and make sure it works properly.

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