How Long Can a Dishwasher Drain Hose Be? (8 Steps to Find Length)

Dishwasher with proper length drain hose

The drain hose is an integral component of a dishwasher because it connects the drain pump to the garbage disposal.

The connection of this hose will depend on the type and model of the dishwasher as well as the plumbing setup around the appliance.

An important factor that affects the drain hose operation is its length.

So, how long can a dishwasher drain hose be?

The Ideal Length of A Dishwasher Drain Hose

Dishwasher drain hoses are usually 6 to 6.5 feet in length. This length is usually enough for the drain water to reach the garbage disposal of the sink. However, if your drainage system is located further away, you should be able to extend the dishwasher drain by another four to six feet by using the right accessories.

Now, the diameter of the dishwasher drain hose will usually be half-an-inch, which makes it convenient to connect to ½-inch, ¾-inch, and 1-inch pipes.

How to Measure the Ideal Length of The Dishwasher Drain Hose?

Most dishwasher brands allow enough length for the hose to reach the garbage disposal system.

Hence, it’s usually easy to install in most cases.

Nevertheless, it makes sense to measure the length of the dishwasher drain hose and make sure it’s ideal before installing your dishwasher for the following reasons.

Short drain hose length or an incorrect configuration can result in improper removal of the discarded water or sewer gases from the system.

Meanwhile, a drain pipe that is too long can get very heavy and strain the brackets.

Let’s look at the different steps to determine the ideal dishwasher drain hose length and how to measure it for proper installation.

1. Calculate the Ideal Length of The Dishwasher Drain Hose for Your Setting

Your dishwasher will ideally come with an attached drain pipe of standard length, usually around 6 feet. This will work in most situations.

However, factors like the sink height and slope of the floor should also be considered when planning the ideal dishwasher drain hose length.

Hence, it’s essential to determine the correct length for the drain hose to ensure that it operates efficiently.

Drain variations, like if there is an air gap, are also factors that will play into consideration.

In these cases, you may have to revise the requirements and customize the drain hose length to work correctly for the given setting.

2. When Measuring, Measure from The Dishwasher to The Drain

To calculate the length of pipe needed, start measuring from the dishwasher connection point behind the appliance to where it attaches to the sink draining system.

This means that you should measure from the dishwasher outlet to the garbage disposal unit or the air gap, as the case is.

Sometimes, there will be a shut-off valve between the two points.

Make sure that you keep it open while measuring to get an accurate idea of the length required.

3. Then, Measure from The Sink to The Drain

Once you know the length of the pipe from the dishwasher to the drain, proceed with measuring the length from the sink to the drainage system of your home.

You will have to measure from the sink or air gap system where the previous measurement ended and continue till you reach the plumbing system.

If you use any accessories along the way, you should accommodate some extra length of pipe for them too.

A few extra centimeters will not usually make a difference.

However, if there is excess piping, you may have to trim the extra length to streamline the water flow.

4. Add Extra Length for The High Loop

Man with measuring tape

Most dishwasher manufacturers specify the requirement for a high loop on the dishwasher drain pipe.

This high loop is also called the air gap.

It’s a critical requirement because it prevents the backflow of the drain water into the dishwasher.

In the absence of a high loop, the disposed water can re-enter the dishwasher and contaminate the inside of the dishwasher.

It will also result in water logging.

So, all leading dishwasher manufacturers specify that you install a high loop on the discharge side of the drain pipe before connecting it to the drainage system.

The drain that is looped high on the side of the dishwasher isn’t a substitute for this high loop on the discharging end.

When a high loop is absent, the dishwasher will often need an air gap, which is a device mounted on top of the kitchen sink that serves the same purpose.

5. Add a Few Extra Inches to Be on The Safe Side

Once you have measured the pipe from the dishwasher to the drain and the drain to the sink, add a few extra inches for each connection point.

Expert plumbers recommend adding an extra inch to your measurements at every connection point to accommodate the extra pipe length that will be necessary where the dishwasher connects to the sink and the sink to the drain.

This will give you the total length you need for the dishwasher hose pipe.

The few extra inches will account for any small errors that you may have made while making the measurements.

6. Accommodate the Presence of An Air Gap

If there is an air gap connection in the drainage system of the dishwasher, the calculation for the length of the drain hose is different.

In this case, you must consider two lengths. The first length will be from the drain outlet to the first extremity of the air gap.

The second length will be from the other extremity to the garbage disposal system.

You must measure both these lengths separately to decide the total length of the drain hose that is necessary.

Additionally, you will also need hose clamps to attach the drain pipe to the air gap at either end.

7. Add a Y-Clamp if It’s Absent

When connecting the hose from the air gap to the drain pipe, you must hook the larger end of the air gap to a Y-branch tailpiece.

If this Y-branch is absent, you will have to install it separately for the drain hose pipe to operate as intended.

The Y-branch piece must be attached to the sink drain using a 7/8-inch rubber hose.

In addition, you will also need hose clamps to secure the rubber hose in place.

If the hose is too long after adjusting for these settings, trim the extra length of the pipe so that it fits correctly.

8. For Longer Hose Pipes, Choose Strong and Rugged Pipes for Connections

Most drain hose pipes are made of corrugated plastic.

Corrugated plastic has ridges on the surface that allow the material to tolerate the water pressure.

However, these corrugations may give way and collapse over time if the pipe is too long.

So it’s better to choose a drain pipe made of stronger materials if it’s too long.

Reinforced vinyl tubing is usually the best choice for such needs.

This material is stronger than corrugated plastic and can tolerate higher water pressure without collapsing.

Reinforced vinyl tubing is also the better choice when multiple connections must be made in sequence between various drainage points at the outlet of the dishwasher.