Diagnosis
The flow restrictor in the faucet aerator is clogged with scale or sediment. This is the most common cause of slow flow on an otherwise working system.
How to Fix It
Unscrew the aerator from the tip of the faucet spout. Soak it in a bowl of white vinegar for 30 minutes. Use an old toothbrush to scrub the small screen. Rinse thoroughly and screw it back on hand-tight.
If That Didn't Work
The storage tank's air pressure may be too high. Shut off the water and drain the tank completely. Use a tire pressure gauge on the Schrader valve (like a bike tire valve) at the top of the blue tank. It should read 6-8 PSI when empty. If higher, bleed air out until correct.
Heads Up
Never use CLR or harsh chemicals on the aerator. They can damage the plastic and leave a residue. White vinegar is safe for the food-grade materials.