Depending on which type it is, it either need a new washer or seat in the valve. The washer is a flat rubber disk that seals when you turn the faucet off and the seat is a small rubber cup that does the same thing.
The faucet drips even when the water is turned off.
A water faucet is the mechanical device fitted to the water supply pipes over bathroom and kitchen sinks. When turned on they supply water.
Seperate valve for outside faucet turned off, broken valve stem inside of outside faucet or handle stripped at faucet.
He turned on the faucet but only a trickle of water came out.
A water faucet utilizes mechanical energy, which is a form of kinetic energy generated by the movement of water through the faucet. When the faucet is turned on, potential energy stored in the water in the pipes is converted into kinetic energy as the water flows out of the faucet. This mechanical energy can then be used to perform work, such as filling a container or powering a water-based appliance.
Dripping, perhaps.
If you have an instantaneous hot water heater, and your faucet doesn't flow enough water it won't turn on the water heater. Thus requiring another faucet to be turned on.
Its a loss in water pressure to the shower.
To drain the water that is in the pipe or spout..
When your faucets are off, the water is sitting still. As soon as you open a faucet, water starts flowing out due to the pressure created by your water pump. Whenever you turn the water faucet off, the water supply is cut at the spigot and now all that water that was moving has now stopped, suddenly. Sometimes, when the pressure is too high, it can cause what is called water hammer. Water hammer is when a faucet is turned off, a shockwave is sent through the pipes, vibrating them sometimes throughout the entire house.
I just brought a Glacier Bay pull down ceramic kitchen faucet Model 896408. After installing it, the cold water wasn't coming out of the faucet. It turned out the problem was the coldwater supply line inside the faucet was bent & twisted. As a result, when the body of the faucet was attached, it had to be turned just a little to position it correctly, this tighted and choked the water supply line even more- which meant "no cold water." Waiting on replacement line from Glacier Bay, which, I am certain, will correct the problem.
You probably need new gaskets in your faucet.