Diagnosis
Clogged filter or air lock. A brand new filter can sometimes have packing material or dense carbon that restricts flow initially. More commonly, an air bubble is trapped in the system.
How to Fix It
Prime the filter. Remove it from the housing. Hold it under a gentle stream of cool tap water for 30-60 seconds, rotating it to wet all sides. This pre-soaks the media and clears fine dust. Reinstall and try again.
If That Didn't Work
Check for a kink or obstruction in the clear silicone tubing inside the unit that runs from the filter housing to the spout. You'll need to lift the reservoir off the base to see it—ensure it's not pinched.
Heads Up
Flow will always be slower than an unfiltered pitcher—it's a trade-off for the 5-stage filtration. But it shouldn't be a mere trickle. If priming doesn't help, the filter might be defective; contact ZeroWater for a swap.