Washing machine leaking from underneath
Water on the floor almost never starts where the puddle is. The shape of the cabinet means a leak at the back arrives at the front, so the useful question is when it happens.
What it usually means
A washing machine is a steel box with a sloping floor and a plinth across the front, so wherever water starts it runs forward and appears under the door. That geometry is why the puddle tells you almost nothing and the timing tells you almost everything: what matters is which part of the cycle the water arrives in, because each part of the cycle pressurises a different set of components.
Water appearing as soon as the machine fills points at the mains side — the inlet hose connections at the back and the valve they screw into. Those are the only parts under mains pressure, so their leaks do not stop and they produce the most water fastest.
Water appearing during the wash points at the tub, the sump hose that runs from the bottom of it to the pump, and the clips holding both. This is where a coin that has escaped the drum ends up, and a jagged edge working against a rubber hose eventually wins.
Water appearing at the spin points at the pump housing and, more often than anything else on this page, at the filter cap. If it has been out for cleaning and gone back cross-threaded or without its seal seated, it holds water perfectly well at rest and pushes it out the moment the pump runs.
And water appearing at the front of the drum rather than from below is not this fault at all — that is the door seal, or the detergent drawer overflowing back into the cabinet, and both are worth checking with a torch before you pull the machine out.
One cause needs no broken part at all. Too much detergent produces foam that climbs above the tub and escapes through openings that handle water without complaint, and the giveaway is that it happens on some washes and not others. Many machines also have a float in a base tray that stops everything and reports a leak — Bosch as E23, Zanussi as EF3, Miele as F138. That is protection working, and it needs the leak found rather than the tray emptied.
How to narrow it down
Work through these in order.
At what point in the cycle does the water appear?
This is the question worth answering properly, even if it means standing and watching a wash through with a torch and a piece of kitchen roll. Filling, washing and spinning each pressurise different parts, so knowing which one wets the floor narrows the search from the whole machine to two or three components.
Has the filter cap been out recently?
Take it out and put it back deliberately: seal seated in its groove, cap turned fully home, no fibre trapped on the thread. A cap that is a quarter turn short or has its seal rolled will not drip at all while the machine sits and will push water out under the pump’s pressure at every spin.
Is the water clean or soapy?
Clean water with no suds in it has come off the mains side before it ever reached the drum, which means the inlet hoses and the valve at the back. Grey, soapy water has been round the wash, so it is escaping from the tub, the sump hose, the pump or its filter.
How much detergent goes in?
Foam escapes past seals that hold water without difficulty, and the pattern to look for is a leak on some loads and not others. Cut the dose to what the packet says for your water hardness, run a hot wash with nothing in the drawer to clear what is already in there, and see whether the leak follows.
Is it actually coming from the door seal?
Run a finger round the inside of the rubber boot at the front, feeling for grit, a trapped coin or a split at the bottom edge where the seal folds. A perished door seal leaks down the front of the glass onto the floor and looks from a distance exactly like a leak from underneath.
Has anything been moved recently?
Pulling a machine out to clean behind it, or a kitchen fitter working on the plumbing, will loosen an inlet connection or crush the waste hose against the wall. Check both hose unions at the back by hand — finger tight plus a nip is the intent, not spanner tight — and look for a hose kinked flat behind the cabinet.
Has the machine stopped and shown a code?
Bosch E23, Zanussi EF3, Miele F138 and Beko E12 all mean water has been detected where there should be none, and the machine has shut itself down on purpose. Do not clear it and carry on: the code is the only evidence you have of where the water went, and the protection is what is currently containing the damage.
Codes commonly shown with this
- E23BoschWater has been detected in the base of the machine and the AquaStop system has cut in. Bosch say to turn the tap off immediately and stop using it until it is repaired.Stop — call an engineer
- EF3ZanussiThe Aqua Control leak protection has triggered and put the machine into a safety mode. Turn the water off at the tap and stop using it.Stop — call an engineer
- E5BekoBeko give E5 as a clogged pump filter. This is the drainage code that most people arrive at through E18, and unlike E18 it really does mean the filter.Get it checked
- E12BekoBeko record E12 when there may be water inside the machine. Their first instruction is to unplug it, and their second is to look underneath.Get it checked
- F373MieleA leak at the drain filter. Miele give one cause and one remedy: the filter has not been screwed tight. Usually seen the day after cleaning it.Get it checked
- F138MieleThe Waterproof system has found water in the floor tray. Close the stopcock and unplug — the drain pump keeps running until you do.Get it checked
When it is urgent
Take care
What it costs
Typical repair cost
£0–£200
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Get an engineer to look at this
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.