DIAGNOSIS Water is escaping from the internal water tank or its connecting tubes. A crack in the plastic tank or a failed seal at the heating element junction is the most common cause.
FIX Unplug the machine. Dry the exterior completely. Fill the water tank only halfway. Place the machine on a dry paper towel. Do not turn it on. Wait 15 minutes. Check the towel for fresh water spots. This isolates a tank crack or cold leak from a heating-system leak.
IF THAT DIDN'T WORK If it only leaks when heating, the leak is from the heating system. Likely points are the seal where the aluminum boiler meets the plastic tank, or a pinhole in the boiler tube.
HEADS UP Do not operate a leaking machine. Water inside the base creates an electrocution hazard and will damage the internal components. This requires disassembly and repair by an authorized service center.