Dishwasher Leaking? Safe First Steps and When to Call a Plumber

A dishwasher leaking onto the kitchen floor is usually down to one of a few things: a worn or split supply hose, a loose connection at the valve under the sink, a door seal that’s no longer sealing, or water that’s crept into the base of the machine and set off its anti-flood protection. Because dishwashers sit snugly between cupboards, the water you can see is often only part of it, so the aim is to stop the supply first, then check the units around it. If you live in Clare, Sudbury, Cavendish, Lavenham or a village nearby, here’s a simple order to work through.

Dishwasher leaking? Clues to where the water is coming from

• Water pooling at the front, under the door, often after a wash, tends to be the door seal, too much or the wrong detergent (hand-washing liquid makes heavy suds), or a machine that isn’t level. These are appliance issues, so check the manufacturer’s user manual first.
• Damp under the sink, around the shut-off valve points to the supply connection or the hose end, which is plumbing rather than the appliance.
• A swollen or stained kickboard, or a soft cupboard base next to the machine, suggests a slow leak that’s been going on unnoticed for a while.
• The machine shows a fault code, won’t start, or its pump keeps running with the door shut. Many dishwashers have a tray and float in the base that stops the water supply when a leak is detected. Your manual will explain what the code means; don’t try to empty or bypass that tray yourself.

Step by step: what to do first

1. Stay clear of wet electrics. A dishwasher plug is often tucked inside the next cupboard or wired to a switched spur above the worktop. If there’s any water near the socket, spur or plug, don’t touch them. Switch off at the consumer unit (fuse box) only if you can do it while standing somewhere completely dry.
2. If everything electrical is dry, switch the dishwasher off at the spur or wall socket and cancel the programme.
3. Close the valve under the sink. Most dishwashers are fed from a small isolation valve on the pipework under the kitchen sink, often with a blue or white lever, a round tap head or a screwdriver slot. Turn it gently until it’s closed; a lever usually ends up across the pipe. If it’s stiff, leave it rather than forcing it.
4. Can’t find a valve, or it won’t close? Turn off your inside stopcock. In many homes it’s in the same cupboard under the kitchen sink. Our guide on how to find and turn off your stopcock will help, and if it’s stuck, see what to do about a seized stopcock.
5. Soak up and look along the run of cupboards. Lay towels down, then check the base of the sink unit and the cupboards either side. Kitchen carcasses and plinths are often chipboard or MDF, which swells when it stays wet, so dry things out sooner rather than later.
6. Note what you can see without moving the machine. Is the supply hose kinked or bulging? Is the hose end damp at the valve? Is there water on the door seal? A couple of photos taken from a dry spot help us bring the right parts.
7. Don’t slide the dishwasher out yourself. Integrated machines are usually screwed to the worktop and connected to hoses and a cable at the back, and pulling one out can strain the connections or the cable.
8. Leave it switched off until the leak has been found and anything electrical that got wet has been checked.

Avoid these mistakes

• Don’t reset a tripped RCD or breaker more than once. If it trips again, leave it off and call a registered (Part P) electrician.
• Don’t run another cycle to “find” the leak. Each fill can push more water under the units.
• Don’t take panels off the dishwasher or open the base. Anything inside the machine, including the door seal, float and anti-flood parts, is for the manufacturer or a qualified appliance engineer.
• Don’t fit a hose or valve that isn’t made for drinking-water supplies. Under the Water Supply (Water Fittings) Regulations 1999, fittings on your supply must be suitable, properly installed and protected against backflow.

When to stop and call us

• The valve under the sink won’t close, won’t shut fully, or is weeping itself.
• The leak is on the pipework or connection rather than inside the dishwasher.
• You’d like a new isolation valve, a fresh supply connection, or a dishwasher plumbed in properly.
• The cupboards, floor or a ceiling below are damp and you can’t tell how far the water has gone. Our leak detection service can trace it.
• The water won’t stop. Read what to do with a flood or burst pipe and call our emergency plumbing team.
• Your washing machine is plumbed in next to it and leaking too. Our tips for a washing machine leaking cover that appliance.
• You think the leak might be outside your home. A water meter leak check helps, and ask neighbours whether they’re affected too. A leak on the water company’s side of the outside stop tap is for Anglian Water or Essex & Suffolk Water to deal with. That tap usually needs a special key, so don’t dig it up or force it.

Smell gas or suspect carbon monoxide? Leave the property, open doors and windows if it’s safe, don’t use light switches or naked flames, turn the gas off at the meter only if it’s safe to do so, and call the National Gas Emergency Service on 0800 111 999. Get medical advice if anyone has CO symptoms such as headaches, dizziness or nausea. Only a Gas Safe registered engineer may work on gas appliances; you can check an engineer on the Gas Safe Register.

Sources and further reading

• Anglian Water: leakage leaflet
• Electrical Safety First: electrical safety after a flood
• Your dishwasher manufacturer’s user manual, for fault codes, detergent advice and anything inside the appliance.
• Our domestic plumbing services

This is general safety guidance. If you’re unsure, stop and call a qualified engineer.