Coffee Machine Leaking Water: Causes and Repairs
Water under the machine, dripping from the group head or running out of the base is almost always a worn seal, a cracked part or a hose. Where it leaks from tells us most of what we need to know.
What Is Going On?
Leaks are one of the most common reasons people call us, and the first question is always where the water is coming from. Water that drips from the spout or group head after brewing is usually normal, but a pool underneath the machine, water running down the back or a steady drip when the machine is idle is not.
A leak should not be ignored. Water that reaches the electronics can turn a small repair into a large one, and scale and slow leaks can cause corrosion over time.
Safe Checks to Try First
- Check the water tank is seated properly and has no crack, and that its valve is clean.
- Empty the drip tray and check that the tray and its seal are positioned correctly.
- Watch where water first appears: the tank area, the group or portafilter, the steam wand, the base or the back.
- Wipe everything dry and run the machine for a short cycle to find the source.
- Switch off and unplug the machine if water is close to power sockets or the lead.
Common Causes and What We Do About Them
Worn seals and O-rings
Group gaskets, tank seals and brew unit seals harden with heat and time. The most common and cheapest cause.
Cracked or leaking tank
Hairline cracks and a tank valve that no longer seals. Often visible when the tank is held to the light.
Perished hoses and fittings
Internal hoses harden and crack, and fittings loosen with thermal cycling.
Scale damage
Deposits can stop a valve closing or damage a seal, causing weeping that a descale alone will not cure.
Solenoid and valve faults
A valve that no longer closes fully lets water escape where it should not.
Boiler or thermoblock leak
More serious, and usually accompanied by loss of pressure. Stop using the machine.
When to Stop and Call a Technician
If water reaches the power socket, the control board or comes from a boiler or heating block, switch the machine off at the wall and do not use it again until it is repaired.
We diagnose first and give you a written quote before any work begins. Every repair carries our 6-month guarantee on parts and workmanship. See our main coffee machine repairs page for how we work, or contact us to book.
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Where to Go Next
Coffee Machine Leaking Water FAQs
The usual causes are a worn seal, a cracked tank or a perished internal hose. A diagnostic will identify which.
It can be, if water reaches the electronics or the power socket. Switch it off and unplug it until it has been checked.
Only if scale is preventing a valve or seal from working. Most leaks are caused by worn parts that need replacing.