Washing Machine Leaking From Underneath? Find the Cause Fast
Water pooling under the washing machine? How to make it safe, then work out whether it is the fill hose, the valve, the waste pipe, a blocked drain or the machine itself, and who to call for each.
A washing machine leaking from underneath is most often caused by something outside the machine: a loose or split fill hose, a leaking supply valve, a waste hose that has slipped out of the standpipe, or a partly blocked waste pipe that overflows when the machine pumps out. Switch the machine off at the socket, turn off the supply valve behind it and dry the floor. Then check when the water appears. Leaks while filling point to the supply side, leaks while draining point to the waste side, and leaks during the wash usually point to the machine itself.
Key Takeaways
- Unplug the machine and turn off the valve behind it before touching anything wet.
- When the leak happens tells you where it is: filling, washing or draining.
- Fill hoses, supply valves, waste pipes and blocked drains are plumbing jobs.
- Door seals, internal pumps and cracked drums are appliance repairs.
- A slow leak under a machine can rot floorboards and reach the flat below without showing on the surface.
A washing machine leaking from underneath is usually leaking from the plumbing around it rather than the machine itself: a loose or split fill hose, a dripping supply valve, a waste hose that has slipped out of the standpipe, or a partly blocked waste pipe that overflows when the machine pumps out. Unplug the machine, turn off the valve behind it and dry the floor. Then notice when the water appears. Filling points to the supply side, draining points to the waste side, and water during the wash itself usually means the machine.
What to do right now
Switch off at the socket
Water and electrics do not mix. If the socket or plug is wet, switch off the circuit at the consumer unit before touching it.
Turn off the supply valve
There is usually a small valve with a blue or red lever on the pipe behind the machine or under the sink. Turn the lever so it sits across the pipe. If you cannot find it or it will not turn, use the main stopcock.
Drain and pull the machine out
If the drum is full, use the emergency drain on the front filter, with towels and a shallow tray. Then carefully pull the machine out so you can see the hoses.
Dry everything
Wipe the floor, the hoses and the pipes behind. You need a dry starting point to see where fresh water comes from.
When does it leak?
If the source is not obvious, run a short, empty rinse programme with the machine pulled out and watch it. The timing of the leak is the best clue.
| When water appears | Likely cause | Plumbing or appliance? |
|---|---|---|
| Even when the machine is off | Supply valve, fill hose connection or a pipe behind the machine | Plumbing |
| While the machine fills | Fill hose washer, split hose, or the inlet valve on the machine | Usually plumbing, sometimes appliance |
| While draining or spinning | Waste hose out of the standpipe, blocked standpipe or trap, cracked waste hose | Plumbing |
| Kitchen sink backs up when the machine drains | Blocked shared waste pipe | Plumbing |
| From the front, around the door | Door seal torn or dirty, detergent drawer overflowing | Appliance |
| From underneath during the wash | Internal hose, pump or tub | Appliance |
Supply side: hoses and valves
Fill hose
The fill hose connects the machine to the cold supply valve. Each end has a rubber washer, and those washers harden and split over time. A drip at either end is often just a washer, or a connection that has worked loose when the machine was moved. Hand-tighten the connection. If it still drips, the washer or hose needs replacing. A hose that is bulging, cracked or kinked should be replaced, not taped.
Supply valve
The small valve the hose screws onto can leak from its spindle or its compression joint, just like a stopcock. These valves are often decades old, have rarely been turned, and start dripping the day someone turns them off. If yours is weeping, corroded, or will not fully shut, it should be replaced. It is a quick job, but it means turning the water off to the house first. Our guide to a leaking stopcock explains the same kind of spindle leak.
Pipes behind the machine
In many London kitchens the supply and waste pipes run behind the machine and under the units, where a slow leak can go unnoticed for months. If the floor stays wet with the machine unplugged and the valve off, the leak is on the pipework rather than the machine. That is a job for a plumber, and if the leak is hidden, leak detection can find it without pulling out the kitchen.
Waste side: standpipe, trap and drain
Washing machines pump waste water out fast. Anything that slows the waste down can make it overflow.
- Waste hose slipped out: the curved end of the hose should sit securely in the standpipe or be clipped to the sink trap. If it has worked loose, water can splash out during pumping.
- Blocked standpipe or trap: lint, detergent residue and grease build up in the standpipe trap and the sink waste. The water rises faster than it can drain and spills over the top.
- Shared waste pipe blocked: if the kitchen sink gurgles or fills with dirty water when the machine drains, the pipe they share is partly blocked. Our guide to a blocked kitchen sink covers what you can try, and we clear blocked sinks and waste pipes when it will not shift.
- Standpipe too short or too low: in some installs the standpipe is not tall enough, so water siphons or overflows. It may never have been right.
If the machine also smells of drains, see our guide to a sewer smell from the washing machine, because the cause is often a trap problem on the same pipe.
Leaks from inside the machine
If the supply and waste are dry and the water still appears, the leak is likely inside the machine. Common causes are a torn door seal, a blocked or cracked filter housing, a failed drain pump, a split internal hose, or too much detergent causing suds to escape. Check the front filter first, as a filter cap that has not been screwed back properly is a common and easy fix. Beyond that, it is an appliance repair. If the machine is still under warranty, contact the manufacturer before anyone opens it.
Hidden damage and flats
A leak under a washing machine is easy to underestimate. Water spreads under the machine and the kitchen units, soaks into chipboard plinths and floorboards, and can reach the ceiling below in a flat before you notice anything above. Signs it has been going on for a while include swollen kitchen plinths, a soft or springy floor, a musty smell, or a stain on the ceiling of the room below.
If you are in a flat, tell your neighbour below and your managing agent if water may have got through. If you rent, report it to your landlord in writing. Keep photos of the leak and any damage in case you need to make an insurance claim, and read our guide on whether home insurance covers plumbing leaks.
Water under the washing machine again?
Tell us when the leak happens, whether the sink backs up and if water may have reached the floor below. We'll arrange a plumber and confirm the price before any work starts. Our labour is £95 an hour, and the £60 call-out is waived on jobs over two hours.
📞 Call 020 7870 3200More on our water leak repair and kitchen plumbing services.
Frequently Asked Questions
Why is my washing machine leaking from underneath?
The most common causes are a loose or split fill hose, a leaking supply valve, a waste hose that has slipped out of the standpipe or sink trap, or a partly blocked waste pipe that overflows when the machine drains. If all of those are dry, the leak may be inside the machine, such as the pump, a hose inside the casing or the door seal.
Why does my washing machine only leak when draining?
A leak that only appears when the machine pumps out usually points to the waste side: the waste hose has come out of the standpipe, the standpipe or sink trap is partly blocked and overflows, or there is a crack in the waste hose. If water backs up into the kitchen sink at the same time, the shared waste pipe is likely blocked.
Can I still use a leaking washing machine?
It is best not to. Even a small leak can soak into floorboards, swell kitchen units and reach electrics or the ceiling below. Unplug the machine, turn off the supply valve and leave it off until the cause is found.
Should I call a plumber or an appliance engineer?
If the water is coming from the supply valve, the fill hose connection, the waste pipe, the standpipe or a blocked drain, that is plumbing. If it is coming from inside the machine, such as the door seal, the pump or a cracked tub, that is an appliance repair, or it may be under the manufacturer's warranty.
How often should washing machine hoses be replaced?
Check the hoses whenever you move the machine, and replace any that are cracked, bulging, kinked or stiff. Many manufacturers recommend using the new hoses supplied with a new machine rather than reusing old ones. A braided or reinforced hose is worth considering where a leak would cause a lot of damage.