Bosch F18 washing machine: what it means & what to check

Stop using it for now. Carrying on with this fault risks further damage or a leak. Switch it off at the wall until it has been looked at.

What F18 actually means

The machine has tried to pump the water out, failed to get rid of it in the expected time, and stopped with the drum still full.

F18 is a drain fault on Bosch (and the related Neff and Siemens machines). The control board watches for the water level to drop once the drain pump runs; when it doesn't, the cycle is halted and the code shown, usually leaving standing water in the drum and a wash that won't spin. It covers the whole drain route \u2014 pump filter, sump hose, pump itself and the waste pipe under the sink.

What F18 looks like on a Bosch washing machine

Most people find this page having searched for what the machine is doing rather than the code itself. On a Bosch washing machine, F18 usually shows up as one or more of these:

Machine door won't open
Door won't lock or click shut
Door lock light flashing
Door stuck shut with the load inside
Won't start even with the door closed
Machine not draining
Water left in the drum at the end of the cycle
Stops mid-cycle full of water

Recognise any of those? That is this fault, and the rest of this page explains what causes it and what you can check yourself.

What usually causes it

Blocked pump filter \u2014 coins, hair clips, screws, buttons
Blocked or kinked waste hose, or a blocked sink spigot/washing machine trap
Something jammed in the pump or sump hose stopping the impeller
Damaged pump impeller, so it spins but shifts no water
Failed drain pump needing replacement

What you can safely check yourself

Work through these in order. Anything beyond this — panels off, testing parts, anything to do with the wiring — is an engineer's job, and not one to attempt with the machine plugged in.

Turn the machine off at the wall for a minute, then power back up \u2014 sometimes it will re-attempt the drain.
Clean the pump filter behind the flap at the bottom front. Have a shallow tray and towels ready, as water will come out.
Check the waste hose isn't kinked, crushed behind the machine or pushed too far down the standpipe.
If the waste connects to the sink trap, check that spigot isn't blocked \u2014 they silt up with grease, and if a blanking crosshair was never cut out of the fitting the machine will never drain properly.
Use the emergency drain/door release if your model has one to get the water and washing out before anything else.

Common questions about Bosch F18

What does F18 mean on a Bosch washing machine?

The machine has tried to pump the water out, failed to get rid of it in the expected time, and stopped with the drum still full. F18 is a drain fault on Bosch (and the related Neff and Siemens machines). The control board watches for the water level to drop once the drain pump runs; when it doesn't, the cycle is halted and the code shown, usually leaving standing water in the drum and a wash that won't spin. It covers the whole drain route \u2014 pump filter, sump hose, pump itself and the waste pipe under the sink.

Can I fix Bosch F18 myself?

There are 5 checks you can safely do yourself first.

Turn the machine off at the wall for a minute, then power back up \u2014 sometimes it will re-attempt the drain.
Clean the pump filter behind the flap at the bottom front. Have a shallow tray and towels ready, as water will come out.
Check the waste hose isn't kinked, crushed behind the machine or pushed too far down the standpipe.
If the waste connects to the sink trap, check that spigot isn't blocked \u2014 they silt up with grease, and if a blanking crosshair was never cut out of the fitting the machine will never drain properly.
Use the emergency drain/door release if your model has one to get the water and washing out before anything else.

This sometimes clears with those checks. If it comes back, it needs looking at properly.

How much does it cost to repair Bosch F18?

£66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Tried the checks and it's still showing F18?

This sometimes clears with the checks above. If it comes back, it needs looking at properly. Then it wants someone who can open it up.

What it costs, before you call: the price is the same whatever the fault turns out to be — £66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Our own engineers, not a call centre. We cover Nottinghamshire, Derbyshire and Leicestershire — most washing machine faults are seen same day or next day.

Call 0115 648 0929 Book online — postcode and number is all we need

Outside our area? The explanation above still stands — take it to a local engineer and tell them the code. Knowing it saves them time and you money.

Other Bosch washing machine codes

All Bosch fault codes and repairs →

What this looks like when it happens

Repairs we cover near you

Written by the engineers at ASAP Repairs, 0115 648 0929. We repair these machines for a living in Nottinghamshire, Derbyshire and Leicestershire.

Bosch F18 error — washing machine