Replacing a Dishwasher: Power, Water, Drain Line and Air Gap Steps

Replacing a dishwasher that has been in a home for quite some time comes down to a short sequence: shut off power and water, disconnect four things, slide the old unit out, and connect three lines to the new one. In a Lowe's "How To Anything" episode, Jackie shows that sequence in a kitchen where the old unit needs an upgrade.

Shutting everything off first

Like many kitchen appliances, the dishwasher requires power, so the first step is to turn off the power. Next, go underneath the sink and shut off the dishwasher's water. Only then does the unit get disconnected: the water supply, the drainage line, the air gap, and the plug.

One tip applies to the water line. Although the water has been shut off, some water still remains in it, so towels go down before it is disconnected.

Taking out the old unit

With the kick plate removed, the water line is visible underneath. The old dishwasher is not hardwired, which means no electrical wire has to be taken out. With the door open, two brackets are visible; unscrewing them lets the whole unit come out.

What the new dishwasher needs

The new dishwasher arrives wrapped in fabric. That is not packaging but insulation, which reduces vibration and therefore sound, so it stays on.

Most dishwashers don't come with a water line, so one is bought along with the unit. Three connections are needed: the water line, a power cord that plugs in so the dishwasher can run, and a drainage line that is threaded through and attached to the air gap.

Connecting the lines

At the back, where the water line connects, an elbow is screwed on with a couple of twists and positioned to face the right direction. A wrench then gives it a last tightening so it does not move. The water line attaches to the elbow, and the power cord is put in at its connection.

Everything is fed through the back so it ends up under the sink, in this order: the power cord, then the water line, and the drainage line last.

Under the sink, the drain line connects to the air gap. The small side of the air gap is for the dishwasher and the large side is for the sink. The connections are tightened, the line is looped back up, and the air gap is secured.

Securing the dishwasher

The dishwasher is fastened to the countertop using brackets from a dishwasher installation kit bought at Lowe's. The last step is to run a cycle on the newly installed dishwasher.