Bosch Washing Machine E18 Error? Clear the Drain Fault Yourself

The cycle stops part way through, the drum still has water in it, and the display reads E18. It looks like the machine has failed. On most Bosch washers it has not: E18 means the machine tried to pump the water out, watched the level sensor, and did not see the level drop fast enough. Almost always something is in the way.

One question splits this in two. Can you hear the pump running when the machine tries again, a steady electrical whirr from the bottom front? If yes, the pump works and something is restricting the water. If the bottom of the machine is silent, the pump itself or its supply is the problem, and that is a different job.

Start With These 30-Second Checks

1. 1Unplug the machine at the wall before you reach behind it, so a cycle cannot start while your hands are back there.
2. 2Look behind the machine: is the drain hose kinked, crushed against the wall, or pinched under a foot?
3. 3Check how far the drain hose sits in the standpipe. More than about 10 cm and the machine can siphon, which reads as a drain fault.
4. 4Check the hose height. Bosch wants the highest point of the drain hose between 60 and 100 cm off the floor. Too high and the pump cannot lift the water.
5. 5Check whether the standpipe drains freely by pouring a jug of water down it.
6. 6Stand clear, plug it back in, run a drain and spin on its own and listen. A clear whirr with no water moving points at the filter. Silence points at the pump.

1. Empty the Machine Through the Emergency Hose

Every Bosch with a service flap has a short emergency drain hose tucked in beside the filter. It exists for exactly this situation and it is the difference between a controlled job and a flooded kitchen.

1. 1Unplug the machine at the wall. Do not just switch it off at the panel.
2. 2If the cycle stopped during the wash, leave it an hour before you start. The water can be hot.
3. 3Open the service flap at the bottom front. It pops off with a coin or a flat screwdriver in the slot at one edge.
4. 4Find the small hose with a cap, sitting beside the round filter cover. Pull it out to its full length.
5. 5Put a shallow baking tray or roasting tin under it. A bucket will not fit under the lip on most installs.
6. 6Pull the cap off, let the tray fill, push the cap back on, empty the tray, and repeat until nothing more comes out. Expect four or five trays.

2. Open the Pump Filter and Clear It

The filter is the round cover next to the emergency hose. It catches coins, hairclips, screws and the wads of lint that actually cause most E18 codes.

1. 1Confirm the machine is still unplugged before you put a hand behind the flap.
2. 2Keep the tray in place. Even after draining, half a litre sits in the filter housing.
3. 3Turn the filter cover anticlockwise and pull it straight out. It unscrews slowly, and water will follow it.
4. 4Pull out whatever is in the housing. Look for lint packed into a felt disc, which is easy to mistake for part of the filter.
5. 5Rinse the filter under a tap and clear the thread on the cover. Grit on the thread is why people cannot get a seal afterwards.
6. 6Reach into the empty housing with a finger and turn the impeller. It should spin freely with light resistance. A coin wedged against a vane stops it dead.
7. 7Take your hand out, refit the filter cover hand tight, and close the flap before the machine goes anywhere near a socket.

3. Clear the Drain Hose and the Standpipe

If the filter was clean, or if E18 comes back within a few washes after you cleaned it, the restriction is downstream. The pump can only push through what the hose allows.

1. 1Unplug the machine at the wall before you move it or touch the hoses.
2. 2Pull it forward far enough to reach the back without stretching the hoses.
3. 3Trace the drain hose the whole way from the machine to the standpipe or sink trap, feeling for a kink or a hard flattened section.
4. 4Check the standpipe by pouring a full jug down it. It should swallow it without backing up.
5. 5To test the machine's own flow, pull the hose out of the standpipe and wedge the end securely in a bucket so it cannot whip out.
6. 6Step back with both hands clear of the machine and the hose, then plug it in and run a spin and drain. Fast flow here but not before means the standpipe is blocked.
7. 7Unplug again before you refit the hose, no more than 10 cm into the standpipe, with the high point between 60 and 100 cm off the floor.

4. When the Pump Is Silent

If you hear nothing at all from the bottom of the machine when it tries to drain, the filter is not your problem. Either the pump has failed or it is not getting power, and the difference matters for what it costs you.

1. 1Unplug the machine before going any further.
2. 2Clear the filter anyway and turn the impeller by hand. A seized impeller can stall a working motor into silence.
3. 3Take your hand out of the housing, refit the filter cover hand tight and close the service flap. Only then does the plug go back in.
4. 4Check that the machine is not on an extension lead shared with something heavy. A sagging supply shows up as odd faults before it shows up as no power.
5. 5Stand clear and run a drain cycle. If the impeller turned freely and the code returns immediately, stop here. The pump or the board is the next step and both mean panels off.
6. 6Write down your model number from the sticker inside the door before you call anyone. Bosch pumps differ between the 300, 500 and 800 series and the first question will be the model.

5. Clear the Code and Test It Properly

E18 does not always clear itself, and a machine that shows the old code after a good repair sends people back to a filter that is already clean.

1. 1Check the filter cover is seated and the service flap is closed before the plug goes back in.
2. 2Plug the machine back in and turn the dial to off for one minute, which resets the display on most Bosch models.
3. 3Run a rinse and spin with the drum empty and watch the whole cycle out. Do not test on a full load.
4. 4Stand where you can see the drain hose end if possible. Strong, steady flow is what you want, not a dribble.
5. 5Check under the machine with a dry paper towel after the cycle. This is when a crushed filter seal shows itself.
6. 6If the empty rinse passes but a full load errors again, the restriction is partial rather than gone. Go back to the standpipe.

If the machine drains fine but will not spin afterwards, that is a separate symptom with its own causes, and a washer that will not spin covers it. For the general version of this problem on any brand, see a washer that will not drain.

6. When to Call a Pro

The line is clear on this machine. Everything reachable through the service flap is an owner job. Anything that needs the machine tipped or a panel removed is not, because the drain pump on most Bosch models sits under the tub with live connections beside it.

1. 1Call when the filter and hose are demonstrably clear and E18 still appears in the first minutes of a cycle.
2. 2Call when the pump is silent and the impeller turns freely by hand.
3. 3Call immediately if you see water anywhere near the plug or the socket, and leave the machine unplugged until someone has seen it.
4. 4Weigh it up first on an older machine: a pump and labour together can reach $310, which is real money against a machine that owes you nothing.