How to connect dishwasher drain hose to garbage disposal: A step by step guide

Connecting your dishwasher to your garbage disposal can be a convenient way to get it installed in your kitchen as you don’t have to open your drains. Let’s take a look at how this can be done. We have discussed how to install a dishwasher HERE.

 These instructions are used for most dishwasher machines. It is possible that your device works differently. Check the manual of your garbage disposal and dishwasher to make sure that they don’t have other requirements.


Items that are needed to do this installation:

-Hammer and screwdriver

-Drain and retain clamp

-Tape measure

-Drill and drillbit

-Air gap

-Gloves, goggles and protective shoes

Making this connection is often straightforward as you just have to connect two parts with a drain. Let’s see this in more detail:

How to connect a dishwasher to a garbage disposal:

Start by wearing protective equipment. This includes gloves, workshoes, and protective goggles. Turn each device off and unplug it. Close the water supply and drain the lines if needed.

The garbage disposal has often an inlet for the dishwasher. It is possible that this contains a small metal plate. You have to remove this to get started. A hammer and screwdriver make this easy to do. Nose pliers make it easy to retrieve this once it is loose. Make sure to do this as it can cause clogs if you don’t remove it. Check the manual of your garbage disposal to see what needs to happen if this connection is not present. Sometimes it can be added to the pipe itself by adding a T connector but you have to see if that is possible.

Once this is done, it is time to add the dishwasher hose to the garbage disposal. Make sure that you get the right diameter of drain. The drain pipe should also be long enough but don’t have it too long. Most are made out of PP as these can withstand heat. A retaining clamp is used to secure this connection. It is possible to get the drain and retaining clamps in a bundle, this makes sure that you get the right gear. You then tighten the bolt on the clamp with a screwdriver. Check that the hose is hanging securely. Water shouldn’t be able to drip out of it. 

To keep the water flowing, we have to make sure that the drain is secured above the connection point. A simple cord will work. You can also use bungee cords to do this. This makes sure that the water doesn’t get stuck or flow back into the dishwasher. 

 The connection point should be at least 20 inches from the kitchen floor. This makes sure that water doesn’t flow back to the dishwasher. You can add an air gap in the sink to avoid this. You can drill a hole in the sink and add the plastic air gap into it. There are special drill bits for this. The air gap adds air to the drain and this air can push the water down. If there is not enough air, you get a vacuum and the water can get stuck. Water can also flow out of the air gap if needed. Some local codes require that you install an air gap. Air gaps are quite cheap and for this reason, it is recommended that you add them. They can avoid a lot of damage as your dishwasher can break if water flows back into it. 

The drain is then run from the dishwasher to the air gap. A second drain is used to connect the air gap and the garbage disposal. You don’t need to add a P-trap as there should already be one behind the garbage disposal. P-traps keep dirty smells out and this is essential when you have a sink in the kitchen.

If water flows out of the air gap, it can indicate that there is a clog in the drain. You can open the air gap and check the drains to make sure that nothing blocks the water flow. You can use a paper roll and use this to blow into the air gap. This might remove some small pieces of dirt from the pipe. In the video below more solutions are discussed: 

The installation should be done at this point. We can check if there are no leaks and open up the valve. Once this is done, you can activate the devices and let the dishwasher run. Check if there are no leaks. You can do this by running your hand in the cabinet to make sure that nothing feels wet. You will have to inspect this area regularly to make sure that the drain doesn’t drip. Recently sensors have been invented that make this process easier. You can get a notification on your phone when a wet area is detected. This allows you to find a leak early on and avoid expensive damage. These sensors are quite cheap and can be worth it. You can also decide to just check for yourself every week. 

To conclude, we can state that connecting a dishwasher to a garbage disposal is quite easy to do. Just make sure that you add an air gap if needed. The connections should be secure and you have to add a strong clamp so that the hose doesn’t move when the dishwasher is cleaning the dishes. You can contact your plumber if you don’t want to do this installation yourself. They can often do it in less than an hour. It is a great moment to ask for water heater maintenance as well given that plumbers often charge to drive to your home.