Dishwasher Installation Mistakes
Examples of causes of dishwasher leaks or failure

Horrible Dishwasher Drain Hook-Ups

The dishwasher shown above was installed atop a concrete slab and drains out through the adjacent sink trap. That installation, completed in 1998 was replaced with a new dishwasher in 2023. The dishwasher replacement procedure is described in detail

at DISHWASHER INSTALLATION STEP BY STEP

Watch out: But just below we illustrate a different and horrible dishwasher drain arrangement: the installer just dumps the dishwasher into the crawl space beneath the home: an invitation to rot, mold, insect damage. Don't do that.

Mouse Hotel Under the Dishwasher

Not just smells, it's a health hazard.

When inspecting dishwasher drains and drain connections keep an eye open for mouse poop (above).

Nice big openings left between and beneath kitchen cabinets make it easier for the plumber to route dishwasher drain lines but they may also create a winter resort hotel for local mice.

Mouse droppings are not the cleanest environment for your dishes and eating utensils.

Dishwasher installation instructions require the high-routing for the dishwasher flexible drain line connection shown at above right.

This high routing avoids an accidental drain siphon problem (back-draining from a sink into the dishwasher drain line) and it also combines a high location in the cabinet wall with a small penetration opening that make mouse passage more difficult in either direction.

Our photo at left shows a typical dishwasher installation in a new home: while the drain connection (not shown) was routed high and to a sink trap appliance drain tee, the electrical wiring and water supply line were routed through a conveniently big hole in the cabinet side near the bottom.

We like to caulk or seal this opening using spray fire caulk or equivalent as a draft and mouse barrier.

Photo above illustrates connections to an older dishwasher installation in Poughkeepsie, New York.

This dishwasher was connected to a hot water supply using flexible copper tubing and flare fittings: neat, but a lot more labor than using the flexible water supply line currently supplied in a dishwasher installation kit.

Electric Shock Hazards at Dishwashers

Watch out: while the owner (me) served honest notice to potential home buyers that the dishwasher was not in working condition - leaving a note in and on the appliance, I got a nasty shock while rummaging around beneath the dishwasher trying to get it working.

The original installer had "hard-wired" the dishwasher by using a metal junction box left loose on the floor under the unit. All it took was improper grounding and a loose hot wire to create a potentially fatal shock hazard.

Don't go reaching into a wet area containing live wires and plumbing and pipes connected to an electrical ground. Especially if the floor beneath the dishwasher is wet.

Dishwasher Won't Drain

Debris Clogging at the Dishwasher Strainer Leads to Pump Failure & Washing Dishes in Nasty Water

It's remarkable how long a dishwasher may keep working without following the manufacturer's recommendation for cleaning its strainer.

Food and debris collect in the strainer, usually a removable screen in the dishwasher bottom that screens dishwasher drain water before it enters the dishwasher pump.

OPINION: But eventually you're washing your dishes with some pretty nasty water (photo above), even if they look clean at the end of a cycle.

This dishwasher was in continued use but on closer inspection we saw that it was not draining - it was simply using the same dirty water to wash each load of dishes.

Details of how we diagnosed this "dishwasher won't drain" problem and why we decided that the appliance needed to be replaced are found

at DISHWASHER DRAIN CLOG DIAGNOSIS