DIAGNOSIS An internal seal or hose has failed. The most common source is the silicone gasket where the hot water tube connects to the aluminum heating chamber or a crack in the plastic reservoir itself.
FIX Unplug immediately. Turn the machine over and remove the base plate. Look for obvious cracks in the plastic water tank visible from below. If none, you'll need to partially disassemble the upper housing to inspect the tube connections and the large gasket sealing the heating chamber. A failed gasket must be replaced.
IF THAT DIDN'T WORK The leak could be from the anti-drip valve assembly above, with water running down internal channels to the base. Check the brew head area for moisture first.
HEADS UP This is a serious leak risk. Do not continue to use the machine until the source is found and repaired, as water and electricity are involved.