How To Plumb A Dishwasher (Step-By-Step Guide)

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Dishwashers are connected to your home’s plumbing system. As such, when you need a new dishwasher, you will have to connect it to your home’s plumbing system.

Here is a comprehensive guide on how to plumb a dishwasher.

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How to Easily Plumb Your Dishwasher

Plumbing a regular dishwasher & drain

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First, connect the drain hose in the back of the dishwasher into the drain hose next to the air gap.
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Next, connect the larger side of the air gap to the sink drain and make sure that it is connected to the main drain pipe.
3
Next, attach hose clamps to both ends of the tailpieces. Make sure that there are no kinks in the drain pipe. If the hose is too long, you can cut it and reattach the clamps.
4
Run the dishwasher without any dishes in it to make sure that there are no leaks.
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If there is a leak, check the dishwasher hose for any holes and make sure the clamps are fully attached.

Plumbing a kitchen sink with disposal and dishwasher

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First, make sure you cut off the water supply to your kitchens completely before doing anything. Unplug the garbage disposal power cord or turn of the power supply.
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Use a screwdriver to slowly pry the knockout plug out of the hose nozzle and remove the plug with some pliers.
3
Attach the air gap fitting to the proper hole and rotate the nozzles until one is pointing to the garbage disposal.
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Next, attach one side of the garbage disposal hose to the dishwasher and tighten it with a clamp.
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Next, using a knife, cut the hose so that it is a good length and attach it to the open nozzle to the air gap.
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Attach a final hose clamp to the hose over the air gap fitting and make sure there are no kinks in the hose.

How To Plumb A Kitchen Sink With Disposal And Dishwasher

Plumbing in a dishwasher & washing machine together

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First, turn off the main water shut-off valve next to your water meter. Unplug the washing machine and disconnect the cold and hot water lines.
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Next, cut the top 6 inches off the hot water pipeline. Clean the edges and attach the tee splitter fitting. Coat the pipes with soldering paste around the joint. Solder the joints until it is shiny.
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Attach the powerline to your dishwasher. If it is a plug, just plug it into the wall or hardwired the power supply to the power connectors.
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Next, attach the water feed line to the dishwasher and attach it with a compression nut.
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Then, reconnect the washing machine to the water lines and plug it back in. Push the washing machine back into the wall.
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Depending on where your dishwasher is, attach it to your cabinet setup.
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Once everything is connected, turn the water supply back on and check the system for leaks.

Plumbing a table top dishwasher

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First, find the place you want to place the dishwasher on the counter and clear the space. Try to pick a spot that is close to the main sink and has at least 18 inches of clearance below the upper cabinets.
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Remove the sink aerator and replace it with the one that came with the tabletop dishwasher. Connect the adaptor to the faucet with pliers.
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Then, connect your dishwasher to the main water supply. The straight end of the inlet hose should go into the dishwasher. Tighten both ends with a pair of pliers.
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Attach one end of the included drainage hose to the drainage standpipe or the sink. Connect the other end to the back of the dishwasher.
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Turn off the water faucet and check the hose for any leaks—test both hot and cold water.
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Next, plug the dishwasher into an outlet and give it a test run without any dishes. Make sure that those drainage hoses do not leak.

A Dishwashers Mechanical Connections

Power Connection
Dishwashers require 120-volt power to run. The power connection terminals for dishwashers are behind the machine near the floor. Dishwashers can use a standard electrical plug, or they can be hardwired to your home's electrical grid.
Water Supply Connection
Dishwashers require hot water to clean your dishes. You can install a dual valve to your existing water line so you do not have to install an entirely new line for your dishwasher.
Drain Hose Connection
The drain hose siphons water out of the dishwasher when it is done with its cleaning cycle. Drain lines can attach directly to the durian line or run through the garbage disposal with an air gap. Drain hoses attach to the bottom of the dishwasher.

Considerations When Plumbing a Dishwasher

Types of dishwashers

Freestanding
Freestanding dishwashers are separate units that can be bought and installed wherever in your kitchen that you have space and drain hookups. It is basically a complete, self-enclosed unit that is compatible with a wide range of houses and kitchen layouts. These kinds of dishwashers are convenient as you don’t have to do significant remodeling to install them.
Integrated
Integrated dishwashers are designed to mesh with the rest of the kitchen decor. Integrated dishwashers might just look like a cabinet and are typically custom-made and finished. As such, they tend to be more expensive than freestanding models. However, fully integrated dishwashers also tend to be highly efficient and run quietly.
Semi-Integrated
Semi-integrated dishwashers are a middle ground between fully integrated and freestanding dishwashers. They might be matched to kitchen decor, but they also have modular components so they can be moved and modified. Semi-integrated dishwashers are moderately quiet and are relatively easy to install. Semi-integrated dishwashers also sit in the middle of the pricing spectrum.

Dishwasher size

Full Size
A standard full-sized dishwasher is about 24 inches wide, 35 inches tall, and about 24 inches across. Most dishwashers are taller than they are wide, though this is not always true. For example, oversized dishwashers usually come in around 30-32 inches wide.
Slimline
Slimline dishwashers usually measure around 22 inches wide and around 24 inches deep. Slimline dishwashers are normally about as tall as full-sized dishwashers and most kitchen counters are about the same height. Slimline dishwashers might need to have the empty spaces on the side filled to fit into your existing cabinet structure.
Compact
Compact dishwashers are even smaller and typically measure around 18 inches wide and 22 inches deep. The line between slimline and compact dishwashers is fuzzy though compact models typically have less depth. With compact models, you often have to find a way to fill in the empty spaces on the sides.

The tools You'll Need

Adjustable wrenches
Screwdriver
Tape measure
Needle nose pliers
Bubble level
Bucket
Pan
Sponge or towels for residual water

How Much Does It Cost to Plumb a Dishwasher?

It depends on the scale of the renovations that you need. If the dishwasher hookups are already installed in the house, then it will not take much work to get things set up and running. If you have a full-sized standalone dishwasher, you could potentially install it yourself without any professional help for very cheap.

A DIY installation of a fully integrated dishwasher might be hard unless you have remodeling experience in kitchens.

Professional installation for a dishwasher will probably cost around $50-$150 if the hookups are already there. On the other hand, if the hookups are not already in place, then professional installation could cost anywhere between $300-$500, depending on how much remodeling needs to happen.

Ultimately, the right choice is up to you. We would not recommend doing a DIY installation unless you have some prior experience with home projects and installations.

Get a free quote below from a local plumber in your area.

DIY Vs Professional Installation

DIY

Pros

Relatively cheap
Can mostly be done on your own
Fit installation with your schedule
Most dishwasher hookup parts are standard sized and easy to find

Cons

Could involve serious remodeling
Might have trouble attaching water supply and drain lines

Professionals

Pros

Expert installation
Can be done quickly and reliably
Can do extensive remodeling
Can install multiple devices at once

Cons

Possibly expensive
Need to schedule a time
Potential unexpected costs

FAQs

Can you plumb a dishwasher away from the sink?

Yes, most dishwashers come with a 6’ supply line that you can connect to the main drain and water lines of your sink. You can also buy a hose extension if you need more space.

Can I connect the dishwasher directly to the waste pipe?

You can do this, and there are no code violations for doing so. However, you will need to make sure you have the right fitting with a u-bend trap to keep sewer gases from backing up into your kitchen.

Also, if the waste line is not far enough below the dishwasher, wastewater could back up into the machine and your kitchen.

How long does it take to DIY install a dishwasher?

It depends on your experience level with DIY home projects, but it can take anywhere between 2-4 hours, assuming you do not run into any serious problems with installation.

Are most dishwashers plugged in or hardwired?

Most dishwashers are hardwired, though a not insignificant minority use regular 120-volt plugs. If your dishwasher uses a plug, then you will need a nearby outlet under the cabinets.

Conclusion

Dishwashers are a great appliance that can save you time and water. However, you need to make sure that it is installed properly, or you could cause water and waste damage in your kitchen. So make sure that you have a full understanding of the layout and setup you will need to install things.

Ian Haynes

Ian Haynes is an expert writer who has successfully deployed over 500 plumbing pages and other related content. He has an excellent understanding of home plumbing issues and translates his experiences via Plumbing Lab so readers can have a better understanding of common household problems. Outside of his work, Ian likes exploring Brooklyn with his Labrador.