Diagnosis
Cracked reservoir or faulty seal. The most common leak point is the seam at the very bottom of the plastic jug, which can develop a hairline crack from stress or impact.
How to Fix It
Inspect the empty reservoir. Dry it completely, fill it with water, and place it on a dry paper towel. Look for a slow seep, especially along the bottom seam or around the center where it mates with the base.
If That Didn't Work
The leak might be from the silicone seal/gasket where the filter housing meets the reservoir lid. Remove the lid, take out the filter, and check this round, flat seal for tears or misalignment.
Heads Up
If it's the reservoir itself that's cracked, ZeroWater will often send a replacement jug under warranty. The reservoir is considered a separate part from the base and electronics. Have your model number (ZD-018) ready when you contact them.