Standing water in your dishwasher? Here are the most common reasons dishwashers won't drain and how to troubleshoot each one before calling a repair pro.
Opening your dishwasher to find a puddle of dirty water at the bottom is never fun. The good news is that a dishwasher not draining is one of the more common — and often fixable — appliance problems out there. Before you assume the worst, work through these likely causes.
Most modern dishwashers have a removable filter at the bottom of the tub, usually under the lower spray arm. Food particles, grease, and small debris build up here over time and block drainage. Pull it out (check your manual for how it twists or lifts free) and rinse it thoroughly under hot water. This one simple step solves the problem more often than any other fix on this list.
The drain hose carries water from the dishwasher to your garbage disposal or sink drain. If it's kinked behind the appliance, or clogged with food debris and grease, water has nowhere to go. Pull the dishwasher out (unplug it first) and check the hose for sharp bends. You can disconnect it and blow through it or run a plumber's snake through to clear buildup.
If your dishwasher has an air gap — that small cylindrical fitting on your sink or countertop near the faucet — it can get clogged with gunk and stop water from draining properly. Unscrew the cap and check for debris inside. A quick rinse and a check with a toothpick or small brush usually clears it right up.
If your dishwasher drains into a garbage disposal, two things can go wrong. First, the disposal itself might be clogged and backing up water. Try running the disposal to clear it. Second, if you recently installed a new disposal, there's a knockout plug inside the dishwasher inlet that has to be removed before it will drain — many installers forget this step.
The drain pump pushes water out of the dishwasher and into the hose. If it's worn out, jammed, or the motor has failed, water will just sit there. You may hear a humming noise with no water movement, or nothing at all. A drain pump can sometimes be cleared of debris, but if the motor itself is bad, it typically needs replacement.
Many dishwashers have a small check valve (a flap or ball) inside the pump or drain line that prevents dirty water from flowing back into the tub. If it gets stuck closed, water can't drain out. This part is inexpensive but usually requires opening up the dishwasher to access, so it's a good candidate for professional help if you're not comfortable with that.
Older dishwashers without a dedicated drain pump often rely on a drain solenoid or timer to trigger the drain cycle. If this part fails, the dishwasher may run its full cycle but never actually drain. Testing this typically requires a multimeter, so it's often best left to a technician.
If you've cleared the filter, checked the hose, and tested the disposal but water is still pooling, the issue is likely inside the appliance itself — a failing pump, stuck valve, or an electrical/control issue. Standing water left too long can also lead to mold, odors, and rust on the tub floor, so it's worth getting it looked at sooner rather than later. A technician can quickly pinpoint whether it's a simple part replacement or something more involved, and get your dishwasher draining properly again.
