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Dishwasher Drain Without Sink [Solutions & Alternatives]

Dishwashers are relatively a newer concept in the world of appliances.

Even though it wasn’t as available before, it’s gaining huge popularity drastically.

Nowadays a dishwasher is a must-have in any home.

But mostly it’s used with the assistance of a sink. What if you don’t have one?

How does a dishwasher drain without sink work?

A dishwasher drain without a sink needs moderation in four different aspects to work. Supply lines, electricity supply, drainage line, and ventilation need to be adapted. Connect the electricity and water supply to start off the installation process. Then connect the drain hose and test the dishwasher.

Confused? Well, don’t worry! Because we have a whole guide explaining every detail of the complete process.

So, let’s dive right into the details without delaying further!

An Overview of Installing Dishwasher Drain Without a Sink

A big and important part of dishwasher installation is the drainage part. Having a sink right beside your dishwasher just makes it easier. Typically a dishwasher uses the sink’s drainage. The drain of a dishwasher is connected through pipes with the sink’s drain.

But this doesn’t mean that a dishwasher can’t be installed without a sink. If the dishwasher doesn’t have a sink nearby, you need additional plumbing. You need to create a line to the nearest drain which can be anywhere in your kitchen. 

But sometimes doing this can cost quite a lot as the plumbing charge. So consider every aspect before planning to set up your dishwasher. 

Don’t have a sink? Not to worry! Because there are alternatives. Let’s check out the whole process of installing a dishwasher without a sink.

Requirement of Installing Dishwasher Without a Sink

It is possible to install a dishwasher without a sink. There are a few drain requirements that need to be fulfilled. But, it is more complex than the normal installation.

Because there isn’t a sink nearby, additional water system lines will be needed. Also, an additional drain will need to be built on the island.

Dishwasher drains must also be aired, according to several regional construction requirements. For an island dishwasher, an additional air vent may be required.

Let’s check out the four requirements of installing a dishwasher without a sink.

Supply Lines

The first thing that your dishwasher needs is a water supply line. Since we are dealing without a sink here, providing a water supply can be complicated. You will need additional plumbing to create a water supply line.

Remember to extend the line from the nearest water supply line point. Another good way is to bring the water supply from your basement. You can also make sure of the supply line of any water purifier if there is any.

Accessing your basement may be necessary in this case. As well as running hot water from your water heater to the island. Some dishwashers have the ability to heat their water. Which may be preferred if cold water is more easily accessible.

Electricity Supply

Second comes to the electrical supply for your dishwasher. You will need an outlet of at least 20 amp. You preferably should use GFCI-protected outlets, which you may have in your garage. This will reduce the risk of short circuits. Also, keep the GFCI outlets protected.

Because the outlet is in the kitchen, it’s best to be extra cautious. Also, check for the additional electrical requirements for your dishwasher to be installed. Sometimes a lot of dishwashers require a dedicated outlet or electrical supply.

Drainage Line

Though being on an island, a dishwasher may be installed and connected to a sink drain. Normally the dishwasher’s user manual specifies how far a unit may be set from a sink. While still being connected to the drain.

Dishwashers include discharge pumps, which force the water out of the device. This allows you to run the drain line a longer distance. But, it needs to be calculated with the drain hose installed beneath the floor.


The dishwasher’s drain line must be vented to ensure smooth drainage. Otherwise, the wastewater may siphon back to the inside of the dishwater. An island loop vent will be required. Since there is no straightforward connection to a sink vent on the island.

An island loop vent is a piece of pipe. It loops as high as feasible beneath the countertop. So the gap between your countertop and dishwasher can also affect its setup. It supplies as much air as possible to the drain. Through pipes constructed beneath the floor, the loop vent will be connected to the sink vent.

How to Install Dishwasher Without a Sink: 8 Steps

Now that you are aware of the requirements, let’s move on to the steps of installation.

Step 1: Connecting Electrical Supply

Begin by removing the dishwasher’s cover from the access panel. This is located at the very bottom of the machine.  The power cable connection connectors, the water inlet valve, and the drain fittings should all be visible.

If the power cable isn’t already connected to an outlet. Also if the drain hose isn’t connected to the trash disposal or sink drain. You’ll need to create entry holes in the side of the bottom panel. 

Once you have located the connection housing, remove the cover. Connect the power line into the housing. You will see three wires in the colors green, white and black.

Connect the green wire to the green grounding screw. Then the white wire which is a neutral wire to the white dishwasher lead. Lastly, the black wire to the black dishwasher leads.

Step 2: Connecting Water Supply

Your dishwasher connection kit contains a dishwasher 90. This will be used to connect the dishwasher’s water system. Installing the dishwasher 90 is the first step in connecting your dishwasher’s water supply.

Locate the water inlet fitting on the solenoid valve. Apply pipe joint compound to the threads of the dishwashing 90 fitting.

After that, thread it through the solenoid valve. Tighten completely by hand before switching to channel-lock pliers. You may also tighten another 1/4 turn using an adjustable wrench.

The dishwasher connecting kit also contains a braided steel water supply tube. Using a wrench, twist the supply tube coupler nut onto the dishwasher 90 fittings.

This is a compression fitting that does not require a pipe joint compound. It’s crucial not to overtighten the threads, since this may cause them to tear.

Step 3: Connecting the Water Supply Tube

Connect the water supply source you have chosen with the water supply tube of the dishwasher. If your dishwasher requires it, you may need to attach it to a hot water source.

Make sure to check for leaks by turning the shutdown valve. Check for leaks at the opposite end of the supply tube under the dishwasher. If there are leaks in either area, loosen the fittings a bit further.

Step 4: Connecting the Drain Hose

There are different methods of attaching the drain hose. Attaching your dishwasher drain to your sink drain is the simplest and most effective. But here we are concerned about the possible drainage system without a sink.

Also depending on your geographical location, there might be different codes. Many plumbing codes require an air gap fitting to be attached to your dishwasher drain.

In case you are looking for recommended air gap fittings, here are some:

Product 1
Product 2

In that case, you need to set up a sink. Because the air gap doesn’t work without a sink. This becomes easy if you connect it to the sink’s drain. 

There is only one way left through which you can set up the drainage system.

The dishwasher waste line can be looped and secured to the counter’s bottom. Then lower it to connect to the garbage disposal head or the sink drain tailpiece.

This “high loop” serves as an air gap, keeping unclean water out of the dishwasher. Local regulations may not always allow it.

Step 5: Testing the Dishwasher

The last step is to test your dishwasher. Turn on the dishwasher after plugging in the electrical plug. Check if fresh water is going in without any leakage. Also, check for leakage in the way of drainage.

If everything works properly, but the bottom cover of the panel is back on. Place your dishwasher in place.

Your dishwasher is ready to be used. 

Things to Remember

Among all the factors, the placement of your dishwasher is very important. Good placement of your dishwasher can contribute heavily to maximizing convenience and ease.

Dishwasher placement is a vital factor in enhancing the utility and convenience of the machine. Good placement can go a long way. Especially if you want the best possible outcome from your machine.

Placing Dishwasher Next to your Sink

This is the best position you can possibly place your dishwasher in. This drastically increases the efficiency of dishwashing in comparison to any other position in the kitchen. The main reason is connecting the drain to your sink drain.

This makes the whole installation process easier and cheaper. Otherwise, you will need plumbing as we have said earlier.

In terms of usage, it also benefits the user. You can easily scrape off the residue and put it in the dishwasher. So the whole process of dishwashing just becomes easier and faster.

Placing Dishwasher Close to Storage

Typically after the dishwashing is done you will need to move the dishes and store them. So it’s best if you can place your dishwasher close to the storage of the dishes. This way you can save up a lot of time.

Especially in the case of professional kitchens, these efficiency tricks can make a big difference.

Keeping Enough Space for Mobility

Wherever you position the dishwasher, enough space for you to move around is a must. If you are unable to move at ease then it may be quite a struggle. So keep enough room for yourself to move with the dishes.

It can also reduce the chance of accidents by lowering the chance of accidental drops. Also, a standard-size dishwasher can be fitted under most countertops. So ensure enough room for maximum mobility required by the user.


Can I use an air gap without a sink and is it good?

No, you can’t use an air gap without a sink or a countertop. To use an air gap you need a countertop to install it. Air gaps are very effective and the most secure way to prevent wastewater from contaminating freshwater. Some regional codes also mandate air gaps. So consider getting one if you can.

What are the alternatives to the air gap?

There are a few alternatives to the air gap. One has been discussed in this article as well which is a high loop. Another is a standpipe which is commonly used with washing machines. It’s also very common to be used under countertops as an alternative to an air gap.

Is a dishwasher drain trap needed?

The bottom of the trap is always filled with water. This prevents sewage gasses from coming out of the house. The dishwasher drain should be attached before, not after, the P-trap. If not installed correctly then sewer gasses may get out.


That will be all on our guide on dishwasher drain without sink. Hopefully, this guide brought value to you.

Remember to take safety measures while doing the plumbing work or installation. With that note, we wish you all the best.

Hope to see you at the next one! Goodbye!