Hot water tank needs bleed of air,
A leak in the supply pipe.
check for leaks
Lots of stuf can cause it including sediment or a blocked supply line
The simplest answer would be that the screen in the spout is clogged.
Lime buildup in your water lines. No, it wont hurt you.
If there ever was one on the lake it would be a water spout not a tornado. Tornadoes are on land not water. A water spout is on the water.
old galvanized piping
Stopped at all faucets? Didn't pay the water bill. If in cold climate, the line from the outside to probably the water heater has probably frozen.
Do all the faucets do this or just one. if its just one faucet its a problem with this fauset. If its all the faucets in the home its a problem with the main water line coming into your home.
The aerator at the end of the spout is clogged. Unscrew the aerator and blow out the screen. Replace aerator and Voila!
With no air in the system anywhere, there would be nothing to hold pressure, so the slightest leak would cause the system to go to zero.
Undo the aerator at the end of the spout and clean out the screen of the aerator. It is probably plugged up. Run the water without the aerator attached. If you have full pressure, the plugged aerator is the problem. If you do not have full pressure without the aerator on the spout, it could be plugged in the spout. Usually the aerator plugged. Cheers