Clearing a Bosch Dishwasher That Will Not Drain, Step by Step

Before you start

Have a cup, a towel and a shallow tray. Switch the machine off at the wall or the breaker — not because there is any danger in what follows, but because a machine that decides to start a cycle while your hand is in the sump is an unpleasant surprise.

Twenty minutes, no tools, no parts. Four of the five causes end here.

Step 1 — bail it out

You cannot see anything under three inches of gray water and you cannot lift the pump cover with the tub full. A cup and a towel, until the floor of the tub is damp rather than flooded.

If the water is hot, wait. It came from a cycle that stopped part way and it will be at wash temperature.

Step 2 — the filter

In the floor of the tub is a cylindrical filter assembly. It unscrews by hand. Turn it counter-clockwise, lift the whole thing out, and look at what comes with it.

Rinse it under a running tap with a little washing-up liquid and a soft brush — a nail brush is ideal. What you are removing is a mat of food, seeds, labels and grease that has stopped water passing through.

This alone is the answer a large share of the time.

Step 3 — the pump cover

Beside where the filter was is a small plastic cover, usually with an arrow or an unlock symbol on it. It lifts straight out.

Underneath is the drain pump impeller. Clear anything sitting on or around it — the classics are a fragment of glass, a fruit sticker, a cherry stone, and a piece of a plastic lid. Turn the impeller gently with a finger; it should move freely.

Step 4 — refit properly

The cover has to seat and click. This gets its own step because a cover left slightly proud produces exactly the symptom you are trying to fix, and people who have just done everything right assume the machine is broken.

Push it down and turn it until it locks. Then put the filter back and screw it home hand-tight.

Step 5 — the path out

If it still will not drain, the problem is downstream.

• The hose. Pull the machine forward far enough to see behind it. A hose kinked when the machine was last pushed back is common and free to fix.
• The high loop. The hose should rise close to the underside of the counter before dropping to the waste. Without that loop, sink water flows back into the machine — which also explains a dishwasher that smells of the sink.
• The air gap. If there is a small chrome cylinder on the counter beside the tap, take its cap off and clear the debris inside. They block, and when they do the machine cannot drain at all.
• The disposal knockout plug. If a garbage disposal was fitted at any point and the dishwasher has not drained properly since, this is almost certainly it. The disposal ships with a plug in its dishwasher inlet, and whoever connected the hose has to punch it out.

Step 6 — prove it

Run a full cycle, not a rinse, and be in the room when it reaches the drain. It is the only way to know, and it takes an hour of doing something else nearby.

When to stop and call

If the filter and the pump cover were clean, the hose is straight, the air gap is clear and there is no disposal in the story, the pump itself is the likely answer — and that is a part rather than a clean. It is a well-designed replacement and usually a same-visit job.

Photograph the code before you clear it. On this brand the same drain condition is published under several labels depending on the age of the machine, and knowing which one your machine shows tells us which generation of pump to bring.