Dishwasher Not Draining — How to Fix Standing Water
Water pooled in the bottom of the dishwasher after a cycle almost always means a blockage in the drain path — not a dead machine. Before you call for service, work through the filter, the drain hose and air gap, the garbage-disposal connection, and finally the drain pump. Most of these are quick, no-cost fixes.
1. Clean the Filter and Sump
The cylindrical filter in the bottom of the tub traps food debris and grease. Twist it out, rinse it under hot water with a soft brush, and clear any gunk from the sump opening underneath. A clogged filter is the most common reason a dishwasher won't drain and won't clean well. Do this every few weeks as maintenance.
2. Check the Garbage Disposal Knockout Plug
If the dishwasher was recently installed and has never drained properly, the culprit is often the garbage disposal. New disposals ship with a solid knockout plug in the dishwasher inlet that must be removed during installation. If it was missed, the dishwasher has nowhere to drain. Disconnect the dishwasher drain hose at the disposal and confirm the plug was knocked out.
3. Clear the Drain Hose and Air Gap
The drain hose can clog or kink where it loops up under the sink. If you have an air gap (the small cylinder on the countertop next to the faucet), pop the cap and clean any debris inside — a clogged air gap stops drainage and can cause water to back up. Make sure the hose has a high loop so dirty sink water can't siphon back in.
4. Inspect the Drain Pump
If the path is clear and it still won't drain, the drain pump may be jammed or failed. Remove the bottom filter and shine a light into the sump — broken glass or debris can lock the pump impeller. With power off, you can often clear it by hand. If the pump is silent or hums without pumping, it likely needs replacement.
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FAQ
A small amount of clean water in the sump is normal. Dirty standing water means a drain blockage — clean the filter first, then check the drain hose, air gap, and garbage-disposal knockout plug.
Scoop or towel out as much water as you can, then clean the filter and sump. Run a short cycle and stop it at the drain phase to confirm it clears.
Vinegar helps with odor and light mineral buildup but won't clear a physical clog or a stuck pump. Clean the filter and drain path first.
Always unplug an appliance and shut off its water supply before servicing. This guide is informational and not a substitute for a qualified technician.