Dishwasher Won't Drain? Standing-Water Troubleshooting
Quick answer
A dishwasher that won't drain usually has a clogged filter or food trap, a blocked or kinked drain hose, a jammed garbage-disposal knockout plug, or a failed drain pump. Clean the filter at the bottom of the tub first — it resolves the majority of standing-water cases.
A little water in the filter area is normal; a flooded tub after a cycle is not. The drain path runs from the dishwasher filter, through a hose, often via the garbage disposal or an air gap, and out to the drain — and a blockage anywhere along it leaves you with standing water. Most checks are quick and safe.
1. Clean the filter and sump
Remove the bottom rack and twist out the cylindrical filter at the base of the tub. Rinse away food, grease, and debris, and clear the sump area underneath. Clogged filters are by far the most common drain complaint and a five-minute fix.
2. Check the disposal knockout
If you recently installed a new garbage disposal, the dishwasher drain hose connects to it — but the disposal ships with a knockout plug that must be removed. A plug left in place blocks draining entirely.
3. Inspect the drain hose and air gap
Look for kinks where the hose loops under the sink, and clean the air gap (the small cylinder on the countertop or sink) if your setup has one. Both are common, easily overlooked blockage points.
4. Run the disposal
A full or clogged garbage disposal can back water up into the dishwasher. Run the disposal with water, then try the dishwasher's drain cycle again.
When to Call a Specialist
If the filter, hose, air gap, and disposal are all clear but water still stands, the drain pump or its check valve is likely failing, or the control isn't triggering the drain. That's the point to have a technician test and replace the pump.
Frequently Asked Questions
How do I remove the standing water?
Bail out what you can with a cup, then soak up the rest with towels before working on the filter. This keeps the job clean while you clear the blockage.
Is standing water in a dishwasher normal?
A small amount in the filter recess is normal and keeps seals from drying out. A tub-full of water that doesn't clear after a cycle means a drain blockage or pump fault.
Could it be the drain pump?
Yes — if every accessible blockage is cleared and water still won't leave, a failed drain pump or stuck check valve is the likely cause and needs replacement.
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