This article describes the installation of a dishwasher in a newly-built
house. This procedure also applies to a newly remodeled kitchen. Replacing a
dishwasher is quite similar, except that the old appliance needs to be removed
first. That may require turning off a circuit breaker and shutting off the hot
There are 3 basic connections for a dishwasher:
- Hot water supply line.
- Drain hose.
- Electrical supply, which is usually 20 Amps and 120 Volts.
||Before I started drilling holes, I wanted to be sure
the dishwasher actually fit in the cabinet opening.
The standard dishwasher opening is exactly 24" wide and the
height of a standard base cabinet, which is usually close to 34½".
This opening is nothing special... it's just a gap between cabinets.
Installing a new dishwasher in an existing run of cabinets is possible, if there
is a 24" base cabinet adjacent to (or close to) the kitchen sink.
|The only connection that normally comes with dishwashers is
the drain hose. I bought a 6 foot dishwasher supply kit, which came with a
braided steel hose and a brass elbow/adapter fitting.
||All the connection points were under the kitchen sink:
- 1. Hot water shut-off valve.
- 2. Drain connection.
- 3. Electrical outlet.
Because the supply and drain connections were to the left of the center of the
sink, those hoses will dictate how far the dishwasher will be able to extend out
of the cabinet. I could make the electrical lead as long as I wanted, so I did that
For whatever reasons, the electrician just wired up a receptacle below the
sink. One of the plugs is switched (for a future disposal) and the other is
Every time I've installed a dishwasher on my own houses, I've just ran a
12-2G cable from the breaker box to the floor area behind the dishwasher.
One seemingly easy option is to fabricate an extension cord from 12-2G
cable or 12 gauge flexible cord. Installing a male plug on one
end is simple... but there's a drawback to that approach. A plug in the wall
does not make as secure a connection as a permanent wire-nutted installation. I
have seen too many appliance plugs lose their firm contact and begin to
overheat. A permanent connection reduces the risk, however slight, of a fire
caused by a poor-fitting plug.
But in this case I went ahead and made up an extension cord
|I drilled 3 holes, using a 1¼" hole saw that was just
big enough for the drain hose.
||I connected a heavy-duty male plug to one end of an 8-foot
piece of 12-2G cable.
|This little metal box is for the electrical supply
connection. The front panel needed to be removed to reach this box.
||Every dishwasher I've ever seen has a removable front panel.
This GE unit had a deluxe 2-piece panel, which allows for the lower section to be
adjusted up and down to cover any gaps at the bottom.
||I attached a cable clamp to the other end of the cable
(after I threaded it through the hole in the cabinet).
|I connected the respective hot, neutral, and ground wires
with wire nuts.
||I replaced the cover to the connection box. These boxes are
quite small, so there is not much room for excess wire length.
|This blue device is the supply valve. The hot water enters
||That's a 3/8" NPT (National Pipe Thread, also called
Iron Pipe thread) female fitting on
the bottom of the valve. Every dishwasher I've ever seen needs an elbow
fitting to turn the corner. I don't know why the appliance manufacturers
can't just make the valve point to the back.
|I dabbed some pipe thread compound on the fitting and
tightened it. This was tricky because there were no wrench flats on the
valve. Holding the plastic valve body could easily break it. I used a pair
of channel-locks to hold the steel bracket. Iron pipe fittings need to be
pretty tight, end the elbow needs to point towards the back.
||I connected the braided stainless steel supply hose to the
elbow/adapter. This is a 3/8" compression fitting, which requires
less torque than a pipe thread fitting. Some compression fittings, like
this hose, use rubber seals under the hex nut, and excessive tightening
can damage the seal, causing a leak that only gets worse with further
Unfortunately it takes a little experience to become familiar with just how
tight to make these fittings. I've learned my lessons by:
1. Having leaks at fittings that were not tight enough, and
2. Having to run out and buy new
parts after I've damaged them from overtightening.
|I threaded all the hoses through the holes in the cabinet.
||I connected the supply hose.
|The end of the drain hose was too big for the barbed fitting
the plumber installed.
||But the hose end was labeled for different sizes of pipe, so
I just cut at the designated line.
|I secured the drain hose with an automotive-type hose clamp,
which the plumber had left behind with his temporary plug.
||I set the dishwasher in place and turned the leveling screws
to raise it up. I didn't want to leave a big gaping hole at the top, and
the bottom cover panel can be adjusted.
|I positioned the appliance so the door was about 1/16"
away from the cabinet. If the door was too close it might hit the wood
before making a tight seal.
||I installed the two tiny screws that hold the dishwasher in
place. Every dishwasher I've seen just sits in the floor and uses 2 small
wood screws to hold a pair of metal straps to the bottom of the
Then I plugged in the power cord, turned on the water, and ran the machine. I
waited for a full cycle and checked for leaks before replacing the front cover
Notes On Maintenance And Repairs:
When I worked in hotel/condo maintenance, we routinely replaced leaky
dishwasher drain hoses with 7/8" automotive heater hose, which is actually
a hose used on large trucks. This hose is very durable and resists high
temperatures. We would just use automotive hose clamps to fasten the hose ends
to the fittings. Those condos all had garbage disposals, which have a larger
dishwasher drain fitting than is often found in installations such as the house
in this article. In some cases I suspect that 5/8" heater hose might work.
Since any water-using appliance can leak or overfill, I have formed a habit
of only using the dishwasher (and clothes washer) while I am at home. I have
heard of new appliances malfunctioning while people were away and causing
thousands of dollars in flood damage.
HammerZone reader Brent Huhta shared this idea:
"I've found that it is good to apply some varnish or polyurethane
to the front underside edge of the typical Formica-clad particle
board countertop directly above the dishwasher. When the dishwasher
is done and you open it up, you usually get a big cloud of steam coming
out of it. This moisture, over time, makes the particle board swell
if it isn't sealed. Not a major problem, but it's helped me."
- Cordless Drill/Driver
- Adjustable Wrenches
- Channel-Lock Pliers
- Nut Drivers
- Miscellaneous Hand Tools
- Small Level
- Braided Stainless Steel Supply Hose
- Adapter Elbow, 3/8 IP to 3/8
- 12-2G Cable
- Cable Clamp
- Male Plug, Heavy-Duty