The main shut-off valve is closed or the feed water supply is off.
First, check the feed water adapter's built-in shut-off valve. The handle must be vertical to be open. If it's horizontal, turn it. Next, verify the main cold water supply under your sink is fully on. If water flows to the regular faucet, the main supply is good.
- Locate the red feed water tubing connected to the system.
- Follow it back to the brass feed water adapter on your cold water line.
- Ensure the adapter's shut-off handle is in the vertical (open) position.
If that didn't work, the tank may be empty because the system hasn't been producing. Let the faucet open for 30-60 minutes to allow the tank to fill. If still nothing, check for kinks in the red feed water line or the clear faucet output line.
Heads up: Never connect the system to a hot water line. It's designed for cold water supply only, at 40–100°F.