Dishwashers break down in a handful of recognizable ways, and each has its own short list of causes. The three that bring most people to a repair page are water left in the bottom, water on the floor, and a machine that won't do anything at all. Pick the section that matches what you're seeing.
Before any hands-on check, cut the power. Many dishwashers plug in under the sink; others are hardwired and need the breaker switched off. If you'll be working near the water connection, close the supply valve under the sink as well.
Standing water in the bottom
A little moisture in the sump after a cycle is normal. An inch or more of murky water is not.
Clean the filter
Most modern dishwashers have a removable filter in the floor of the tub, usually a cylinder that twists out and a flat mesh screen around it. Pull the lower rack, turn the cylinder counterclockwise, lift it out and rinse both pieces under the tap with a soft brush. Grease, seeds, labels and chips of broken glass all end up there. Lock it back in firmly, because a loose filter lets debris through to the pump.
Sponge out the standing water first so you can see what you're doing.
Check the garbage disposal connection
If the dishwasher empties into a disposal, two things commonly go wrong:
- •A new disposal with its knockout plug still in place. Disposals ship with a plastic plug sealing the dishwasher inlet. If a disposal was just installed and the dishwasher stopped draining right away, suspect this first.
- •A clogged disposal. Run the disposal with cold water for a bit before starting the dishwasher. Food packed in the disposal backs up the dishwasher's drain.
Air gap and high loop
Some sinks have a small chrome cap on the countertop beside the faucet. That's an air gap, and it can clog; the cap pulls off so you can clean inside. Without an air gap, the drain hose under the sink should rise in a high loop fastened to the underside of the counter. A hose that sags to the cabinet floor can let sink water run back into the dishwasher.
Kinks and the pump
Take off the bottom kick panel and follow the drain hose looking for kinks, especially if the dishwasher was recently pushed back into its opening. If the filter, hose and disposal are all clear and you hear a hum during the drain portion with no water moving, the drain pump may be jammed or failed.
Water on the floor
Where the water appears tells you a lot.
At the front edge, under the door
- •Too many suds. Hand dish soap or the wrong detergent makes foam that pushes out past the door. Use only dishwasher detergent. If it happened once, wipe out as much foam as you can and run a rinse cycle with the machine empty.
- •The door gasket. Look for tears, food stuck to the seal, or a gasket pulled out of its channel.
- •A tub that isn't level. If the dishwasher tilts forward, water runs toward the door. Most have adjustable feet behind the kick panel.
- •Big items blocking the spray arm, which can then throw water straight at the door vents.
From underneath
A leak that shows up under the machine, especially partway through a cycle, is more likely the inlet valve, a hose connection, the pump seal or a cracked part of the tub. With the kick panel off, run a short cycle and watch with a flashlight to see where water appears. Keep your hands out while it runs.
In condos and apartments
If there's a unit below yours, close the supply valve under the sink as soon as you notice a leak, and don't run the dishwasher again until the cause is found. Water under a dishwasher can travel along the subfloor and show up in a neighbor's ceiling before you see much on your own floor.
It won't start, or it stops partway
The easy checks
- •Door latch. The door has to close firmly and click. A misaligned latch or a rack sticking out can stop it locking.
- •Control lock or child lock. Many models lock their buttons with a press-and-hold. A small lock symbol usually gives it away.
- •Delay start. If someone set a delay, the machine will simply wait.
- •The wall switch. In many kitchens the dishwasher is wired to a switch next to the disposal switch. Make sure it's on.
- •The breaker or GFCI for the kitchen circuit.
Beeping, blinking or codes
Write down any code along with the model number. Many codes mean the same broad thing across brands (a drain problem, a water supply problem, a leak detected in the base), but the specifics vary. Your manual or the maker's support site will list them.
Starts, then quits
A dishwasher that fills, runs a few minutes and stops may have a water supply problem, a heating fault, or a leak-detection float that has tripped. Some models stop and show a code the moment they sense water in the base pan.
Dishes still dirty
This is often loading or upkeep rather than a failed part:
- •Spray arms that can't turn because a pan handle is in the way.
- •Clogged holes in the spray arms. Pop the arms off and flush them under the tap.
- •Water that starts the cycle cold. Run the kitchen faucet until it's hot before you press start.
- •Old or clumped detergent.
Routine care that prevents calls
- •Clean the filter every few weeks.
- •Scrape plates, but there's no need to pre-rinse them spotless.
- •Run a dishwasher cleaner through the empty machine now and then.
- •Keep rinse aid topped up; it helps drying as well as spotting.
When to call
Book a repair if the dishwasher won't drain with a clean filter and a clear disposal, if it leaks from underneath, if it won't start after you've checked the latch, the locks and the power, or if a code keeps coming back. A technician diagnoses it in your kitchen, explains what failed and quotes the repair, and nothing is done until you approve. Our dishwasher repair page covers the models we work on. Bosch owners will find that brand's codes in the Bosch dishwasher troubleshooting guide, and if the machine is getting on in years, it's worth reading how to weigh repair against replacement.
A few answers
Is it safe to keep using a dishwasher that leaks a little?
Not really. Small leaks grow, and water under a floor can do damage long before it shows.
Why does my dishwasher smell?
A dirty filter and food trapped in the drain path are the usual reasons. Clean the filter and check the disposal connection.