Washing machine not draining: what to check first

Make it safe before you start

Switch the machine off and unplug it before touching the filter, the hose or anything behind it. If the last cycle was a hot wash, give the water an hour to cool. A full drum can hold a lot of water, so have towels, a shallow baking tray and a bucket ready before opening anything at floor level.

Do not start another cycle to see if it clears. Each attempt pushes more water towards the blockage, and if the problem is in the sink waste, that water ends up in the sink, in the cupboard below or on the floor. If water has already reached sockets or an extension lead, keep clear and switch off at the consumer unit first.

Is it the machine or the plumbing?

Most people assume the machine has broken, but a good share of these call-outs turn out to be a blocked waste. Run the kitchen tap for a minute and watch the sink, then check the symptoms below.

Clean the pump filter

Most front-loading machines have a filter behind a small flap at the bottom front corner. It catches coins, hair grips, buttons and fluff before they reach the pump. When it clogs, the pump cannot move water out of the drum.

Many machines have a thin emergency drain hose next to the filter. Pull it out, remove its cap and let the water run into the tray, closing it when the tray is full. When the flow stops, unscrew the filter slowly anticlockwise with a towel underneath, because more water will follow. Clear anything caught in it, rinse it under the tap and check the opening behind it for anything jammed against the pump. Screw it back firmly and make sure it does not leak before you run a rinse and spin.

Your manual shows the exact position and method for your model. If the filter is seized, do not force it with pliers: a cracked filter housing will leak every time the machine runs.

Check the drain hose

Pull the machine out carefully, watching the supply hoses and the plug. The grey drain hose is often kinked or crushed when a machine is pushed back against the wall, especially after it has been moved for cleaning or a new floor.

Take the hose off at the sink or standpipe end with a bowl underneath and look through it. Fluff and detergent residue can build up at the ends. Flush it through at an outside tap or in the bath. While it is off, check the rubber connector on the waste spigot, because that is a common place for a plug of lint to form.

The hose also has to be arranged properly. It should rise to the height given in the manufacturer's instructions before it drops into the waste, and it should not be pushed so far down a standpipe that it seals the pipe. Both affect how the machine drains, and getting them wrong can also cause siphoning and smells.

Check the sink waste or standpipe

Under the sink, the drain hose usually connects to a spigot on the sink trap or waste. Behind the machine, it may drop into an open standpipe with its own trap. Either one can block with lint, fat from the sink and detergent, and once it does the machine is pumping into a pipe that cannot take the water.

If a new trap or sink waste has just been fitted, check the appliance spigot. Many new wastes come with a blanking disc inside the spigot that has to be removed before an appliance is connected. If it was left in, the machine has nowhere to pump.

A blocked sink trap can often be cleared by the methods in our guide on how to unblock a sink. If the sink is fine and the standpipe is slow, its trap can be unscrewed and cleaned in the same way. If water comes back up through the sink when the machine drains, our article on washing machine water backing up into the sink goes through what that pattern means.

Do not pour chemical drain cleaner into the standpipe or the drum. It can damage seals and plastic waste pipes, and anyone who opens the pipework afterwards is exposed to it.

When the blockage is further down

If the sink, the machine and perhaps the dishwasher all drain slowly, the problem is past the trap: in the waste pipe through the wall, or in the drain outside. Look at the gully where the kitchen waste comes out. If it is full or overflowing, the drain beyond it is blocked, and clearing the trap indoors will not help.

A kitchen waste that keeps blocking usually has a build-up of fat or a poor fall on the pipe. Our guide on why drains keep blocking covers what causes repeat blockages and how they are found.

Pump faults and error codes

If the filter is clear, the hose is clear and the sink and standpipe drain freely, the fault is almost certainly inside the machine: a failed drain pump, a blocked sump hose, a door lock that is not releasing, or an electronic problem. Most machines show a drain error code at this point. Codes differ between makes and models, so look yours up in the manual or on the manufacturer's website.

Faults inside the machine belong to the manufacturer or an appliance repair engineer, especially while it is under warranty. Where we help is everything the machine connects to: the drain hose connection, the trap, the standpipe, the waste pipe and the drain.

What a plumber will do

A plumber will check the drain hose route and height, take apart and clear the trap and appliance spigot, test the standpipe and the waste pipe run, and check the gully and drain outside. If the waste was fitted wrongly, for example with too little fall, a missing trap or a hose connected where it siphons, they will put it right. They will then run the machine through a drain and spin while watching the sink and the joints for leaks.

Get it draining again

Loyal Plumbers covers London and everywhere inside the M25, 24 hours a day, with 10 vans on the road. Call 020 4652 8585 and tell us whether the sink is also slow, what the machine does at the drain stage and whether anything was fitted or moved recently.

Our call-out charge is £60, and the engineer explains what they have found and what the work involves before starting. You can read more about our kitchen plumbing and general plumbing work, or our drainage service if the drain outside is blocked.