Dishwasher not draining

What this symptom might mean

A shallow puddle under the lower rack after a cycle is the most common dishwasher complaint, and it is usually a blockage rather than a failed pump. Food and glass fragments collect in the filter and the sump beneath it; the drain hose can kink behind the machine or clog where it joins the sink drain or disposer; and a new disposer installed without its knock-out plug removed will block the dishwasher completely. GE also lists over-sudsing from the wrong detergent as a cause: foam backs up and the pump cannot clear it.

If the filter and hose are clear and the dishwasher still will not empty, the possibilities move inside: a drain pump with a jammed impeller or a failed motor, a check valve stuck shut, or a control that never commands the drain. A dishwasher that has never drained properly since installation may also have the hose routed without the high loop or air gap that lets it empty.

Safe checks you can do first

1. Clean the filter. Remove the lower rack, twist out the cylindrical filter and lift the flat mesh filter beneath it. Rinse both under the tap with a soft brush. Feel around the sump opening (carefully, there can be glass) and remove anything solid.
2. Check the drain hose. Under the sink, look at where the hose enters the disposer or drain tee. Straighten any kink and make sure the hose rises in a high loop near the countertop before dropping to the drain, or passes through an air gap if one is fitted.
3. Clear the air gap. If there is a chrome cap on the sink deck, lift it off and clean out debris.
4. Run the disposer. If the dishwasher drains into a disposer, run it with water for 30 seconds. A full disposer chamber blocks the dishwasher's outlet. If the disposer is new, check the knock-out plug was removed.
5. Detergent. Use only automatic dishwasher detergent in the amount the manual specifies. Hand dish soap or too much powder creates suds that block draining.
6. Cancel and drain. Most models drain when you press Cancel or hold Start for a few seconds. Try it after the filter is clean and see whether the water leaves.

Nothing above involves gas, wiring, refrigerant or removing panels. Those are technician-only: Removing the sump cover or pump from beneath the tub; Electrical testing of the pump or control; Work on household drain plumbing beyond the dishwasher connection.

Repairs a technician may recommend

After inspection, not from the symptom alone.

• Drain pump replacement. When the pump hums or is silent and the path to the sink is clear. The technician clears any impeller jam first; a jam is not a failed pump.
• Drain hose replacement or re-routing. When the hose is clogged internally, split, or installed without a high loop.
• Check valve or sump cleaning. When debris has passed the filter and blocked the valve flap behind the pump.
• Control board or drain relay replacement. When the pump tests fine but is never energised.
• Disposer connection correction. When the knock-out plug is still in place or the connection is blocked. Plumbing beyond the dishwasher connection is a plumber's work.

When to book

Book if water still sits in the tub after you have cleaned both filters, checked the hose under the sink and run a Cancel/drain. Book sooner if the pump hums without moving water or the dishwasher has never drained fully since it was installed. Tell us the model and whether it drains into a disposer or an air gap; it changes what we bring. The diagnostic is $89 and is waived if you proceed with the repair. Dishwasher repair explains what the visit covers, and dishwasher installation covers hose routing on new units.

Questions

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