If you’re getting ready to put in a dishwasher, then knowing how to install a dishwasher drain can be a challenge. You first need to have an alcove that’s close to the kitchen sink so that you can draw hot water from the kitchen supply and connect the dishwasher drain to the sink drain.
The dishwasher drain hose will connect to the sink drain before the P-trap. If the sink has a garbage disposal, you will find an inlet port on the drain hose for it.
However, if you don’t have a garbage disposal, then you’ll need to connect the drain hose to the tailpiece which will require you to install a tee. The drain hose should connect to a fitting called an air gap or it can make a high loop.
These are the steps that you can take to install a dishwasher drain. Keep in mind that some of this work is fairly technical and you may want to reach out to a professional technician for installation if you don’t feel comfortable with the steps in this process.
1. Drill a Hole for the Hose
You may be able to skip this step if you already have an established place for a drain hose. However, if not, then you should use a drill to make a 1 3/8-inch spade hole in the wall between the alcove for the dishwasher and the sink cabinet.
This hole should be about four inches above the bottom of the sink cabinet. Depending on how far away the dishwasher alcove is from the sink, you may need to pass the drain hose through more than one cabinet. If this happens, drill the holes as close to the bottom and back as you can.
2. Prepare the Disposal Inlet or Sink Tailpiece
If you have dishwasher disposal, you’ll connect the drain to a port on the disposal. Remove a plug from the inside of the disposal by using a screwdriver and hammer to break out the plug.
The disc will fall into the disposal where you will have to remove it. It’s a good idea to do this only when the power is turned off to the disposal.
If you don’t have a disposal, you’ll have to install a branch tailpiece to the sink pipe for drainage. Take the P-trap apart using locking pliers. Remove the tailpiece.
Purchase a branch tailpiece that will need to be cut into the same length as the one you removed. Install the new tailpiece on the sink drain, tighten the nut with piers, and reassemble the pipes.
3. Connect the Drain Hose
With the new dishwasher, lay the machine on its side and then put a hose clamp onto the end of the drain outlet.
Slip the clamp over the hose fitting and tighten with a screwdriver. Place the dishwasher in an upright position and then pull the drain hose from under the unit. There may be a molded part to avoid squashing the hose.
Feed the dishwasher drain hose and the hot water supply line into the holes that you drilled in the cabinet. This may be easier if you have a partner available to help you.
4. Hook up the Drain Hose
Secure the drain hose underside of the sink cabinet by using a hose bracket. The hose will form a tall arch but should not kink.
Finally, connect the hose to the drain inlet and secure it in place with a clamp. If you have an air gap model, then you will secure the drain hose to the air gap inlet with a hose clamp.
Now that you have the steps in place for installing a dishwasher drain, you can see that the process is fairly straightforward but does take some technical knowledge and equipment.
If you don’t feel comfortable with any of these steps, then it may be best to reach out to a professional technician.
Installing the drain will typically only take a short amount of time when done by a qualified professional so it’s an efficient process.
If you install the drain on your own but notice that the system leaks, it may also be a good idea to reach out to a professional technician for assistance.