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In short
Start with the filter. Whirlpool lists a clogged filter, debris in the sump, a kinked or blocked drain hose, a problem at the disposal or sink connection, or a jammed drain pump as frequent causes. It says many "clogged dishwasher" complaints start with neglected filters or food debris in the sump. Bosch also says to clean the filter first when water is standing.
For the rest of the machine (Whirlpool brand):
affresh Dishwasher Cleaner, 6 tabletsBefore you start
Whirlpool says to turn off power at the circuit breaker (not just the control panel) and shut off the water at the under-sink valve. Bail out standing water with a cup, and use a turkey baster for the sump. It says not to use drain-opening chemicals inside the dishwasher.
The checks, in order
- Filter and sump. Remove and rinse the filters (see how to clean the filter). With them out, shine a light into the sump and remove food, labels, seeds, toothpicks or glass.
- Run a short rinse. Whirlpool says to listen for the drain pump and see if water remains.
- Drain hose. Check it isn't kinked, crushed or sagging, and that it has a high loop under the counter or a working air gap.
- Disposal knockout plug. If a garbage disposal was just installed, Whirlpool says to make sure its knockout plug was removed. A plug left in blocks drainage completely.
- Sink plumbing. If water spills from the air gap into the sink, Whirlpool says the blockage is downstream in the hose or sink plumbing.
What the symptom tells you (Whirlpool)
| Symptom | Likely cause |
|---|---|
| Small amount of water above the filter | Partial restriction: clean filters and sump, check hose |
| Water near the door opening | Severe blockage or pump not running |
| Humming, no draining | Jammed pump impeller |
| Water backs up from the air gap | Blockage downstream |
| No pump sound during drain | Electrical or control issue: call for service |
Know when to stop. Whirlpool says to stop and call a qualified technician if you smell burning, see damaged wiring, or the breaker trips repeatedly, or if it still won't drain after these checks.
How we work: the checks and the symptom table come from Whirlpool's drain guide; Bosch's maintenance page agrees on cleaning the filter first. We don't test dishwashers ourselves. Sources are listed below.
Questions people ask
Why is there water in the bottom of my dishwasher?
Whirlpool lists a clogged filter, debris in the sump, a kinked or blocked drain hose, a disposal or sink connection problem, or a jammed drain pump.
Can I use drain cleaner in a dishwasher?
No. Whirlpool says not to use drain-opening chemicals inside the dishwasher; they can damage components and create safety hazards.
Why won't my dishwasher drain after a new garbage disposal?
Whirlpool says to check that the disposal's knockout plug was removed. A retained plug blocks drainage completely.
Sources
Last checked Oct 23, 2026. Steps come from Whirlpool's product help pages and Bosch's support pages and manual. Turn off power at the breaker before working on a dishwasher that won't drain.
