Internal tube connection is loose or an O-ring is failed. Diagnose by location.
- If leak occurs during brewing: Check the internal water tube connections (parts like 5513212881, 5513212871). A connection may have come loose.
- If leak occurs after brewing or at idle: The drip tray or its seal is overfull or misaligned. Empty the drip tray and the hidden internal water container behind it.
- If leak occurs during descaling: Normal during some descaling steps if the drip tray is not large enough. Place a towel underneath.
If that didn't work, a cracked water tank (AS13200250) or a failed internal O-ring (5313217741) on the brew unit is likely.
Heads up: Unplug the machine immediately and do not use it until the leak is resolved to avoid electrical hazard.