How to Install a Dishwasher

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How to Install a Dishwasher

When it comes time to replace your old dishwasher, you’ll need to plumb it in to the plumbing system. This can be a DIY project for homeowners who have the necessary tools and experience, but it is also a common job for plumbers. This involves connecting the water supply to the dishwasher and the water connection under your sink. It can be tricky, so read your dishwasher’s manual and take note of the directions when you install a dishwasher.

Dishwasher Installation

A dishwasher is a great time-saving kitchen appliance that saves you energy and water, while also making the job of washing dishes easier. But installing one requires more than just a little planning to ensure everything goes smoothly.

The first step is to determine where the new dishwasher will go. Licensed tradespeople can install the plumbing, drain and power connections – they’ll likely also supply a new power outlet.

Next, prepare your work area with the right tools and materials. Having everything you need lined up before you begin is important to avoid last-minute shopping trips.

Start by removing the front access panel from the base of your dishwasher. With the help of at least one other person, tilt the appliance on its side to make it easier to access.

Route the power cord through the terminal box and complete the electrical connections according to your product’s instructions. The green wire from the appliance’s cord connects to a grounding screw in the terminal box, while the white neutral and black hot wires are joined with twist-on wire connectors or wire nuts.

Water Supply Line to the Dishwasher

Whether you’re installing a new dishwasher or replacing an old one, you need to plumb the water supply line for the appliance. This involves routing a braided steel supply tube through the hole between your sink cabinet and the dishwasher installation location, as well as connecting the hose to a drain hose and turning on the water valve.

Dishwashers are often connected to a hot water line that carries the water from your home’s main source of water. A hot water line is more effective for cleaning dishes and, coupled with the heating cycle of the dishwasher, can also sanitize your dishes.

Connect the supply line to a three-way angle stop, which has two outlets: one for your sink and another for your dishwasher. Wrap the threads of this fitting with Teflon tape to prevent leaks. Screw the tubing onto the angle stop and tighten it with an adjustable wrench.

Dishwasher Drain Line

The drain line for a dishwasher carries wastewater out of the unit and into your plumbing system. But it’s also a source of clogs, leaks and kinks that can cause water to back up into your kitchen.

The solution is to replace your clogged or damaged hose with a new one. This is a fairly straightforward task, but it’s important to get the right hose for your particular appliance.

If your hose is in front of the unit, it’s easiest to pull the dishwasher away from the wall to gain access. However, if the hose is behind the machine, you may have to use a wrench to remove it.

The dishwasher drain hose must either have an air gap device or a high loop before connecting to the sink. The former prevents a siphon break from forming during wastewater backups, while the latter ensures that sanitary wastewater won’t back up into the dishwasher.

Electrical Connections

When you are installing a new dishwasher, it is important to plumb the electrical connections. This involves determining the electrical power source, and whether to hardwire the dishwasher or use an appliance cord that plugs into a wall outlet.

Electric appliances should always be placed on a dedicated circuit that meets local regulations and the National Electrical Code (NEC). Dishwashers should also be GFCI protected.

For a dishwasher to operate safely, it must be connected to a dedicated 120/125-volt, 15-amp circuit. It can either be hard-wired with an NM circuit cable that feeds directly into the wire connection box on the appliance, or it can be hooked up to a standard appliance cord that plugs into a wall socket.

The green wire from the appliance cord should connect to a green grounding screw inside the dishwasher’s junction box; the white neutral wire should be connected to a white dishwasher lead, and the black hot wire should be connected to a black dishwasher lead. These wiring connections are best made using twist on insulated wire connectors.

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Casey Loeber

Casey Loeber is the founder of His mission is to share the best information online about plumbing jobs and help plumbers lead fulfilling careers.

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