DIAGNOSIS The leak is caused by an improper seal between the spigot assembly and the lower chamber's wall. The most common cause is a missing, damaged, or incorrectly installed black rubber washer.
FIX Step 1: Empty the lower chamber. Step 2: Unscrew the spigot's plastic locking nut from the inside of the chamber. Step 3: Remove the spigot. Step 4: Inspect the black rubber washer on the spigot shaft. Step 5: Ensure the washer is seated in the groove and is not cracked or flattened. Step 6: Reinsert the spigot, hand-tighten the locking nut firmly from the inside. Do not overtighten.
IF THAT DIDN'T WORK The chamber's threading or the spigot shaft itself may be cracked. Inspect both for hairline fractures. A cracked lower chamber requires replacement.
HEADS UP The locking nut must be tightened from inside the chamber. Tightening the decorative knob on the outside will not seal the leak.