Dishwasher Not Draining: Error Codes, Causes & Fixes

What this actually means

Understanding the fault

Dishwashers are designed to leave a small amount of water in the sump, which keeps seals from drying out. A genuine drain fault means water sits well above that, often covering the tub floor. Because a dishwasher shares plumbing with the sink, the cause is frequently outside the appliance entirely.

Try these first — they cost nothing

Free checks before you buy any part

Work down the list in order and stop when the symptom clears.

1
Remove and clean the filter assembly
Twist out the cylindrical filter at the tub floor and lift the flat mesh screen beneath it. Rinse both under hot water and scrub with a brush. Food debris here is the most common single cause.
2
Check the disposer knockout plug
If a disposal was installed after the dishwasher, the knockout plug in its inlet may still be in place, leaving the dishwasher nowhere to drain. This catches a lot of people and is a five-minute fix.
3
Clear the air gap
If there is a small chrome cylinder on the counter beside the faucet, pull its cap and clean inside. They clog with debris and back water up into the dishwasher.
4
Run the disposal
A disposal full of waste blocks the shared drain line. Run it fully before rerunning the dishwasher.
5
Check the drain hose high loop
The drain hose should rise up under the counter before dropping to the disposer or standpipe. Without that loop, sink water siphons back into the dishwasher.

No code on the display?

When your appliance shows nothing at all

Many dishwashers show nothing and simply leave water behind. Every check above still applies. If the filter is clean and the disposal path is clear, the drain pump or the sump check valve is the next suspect.

Where to look

Common causes to check

1Clogged filter assembly or sump screen
2Disposer knockout plug never removed
3Blocked air gap on the countertop
4Kinked drain hose or missing high loop
5Full or clogged garbage disposal
6Failed drain pump or jammed impeller
7Stuck check valve allowing backflow

Know where to stop

When to call a professional

If the drain path is verified clear and the pump does not run, testing means working in a wet cabinet near live connections. Worth handing off, particularly on integrated units that must be unmounted to service.

Read the full safety disclaimer

Match your code

8 related Dishwasher error codes

If your appliance displayed a code, find it here for the diagnostic sequence specific to your brand. Codes vary by model, so confirm the full model number before ordering any part.

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