It Is Good To First Establish The Type Of Faucet Since They Vary. And Because They Are Complex On Their Own, Professional Plumber Service Is Needed.
This type of faucet contains either single or double handles. Inside this type of a faucet is a stem cartridge that regulates the flow of water. The single handled cartridge type operates up and down so as to regulate the flow of water, then left and right to control the temperature. The double handled cartridge faucet has two handles both cold and hot. This type of faucet stops water without having to turn off.
This works just like the double handled cartridge faucet which has both handles for both hot and cold. Each handle contains a valve inside that opens to allow water to flow and also close to block the flow. At the base, there is a rubber washer to prevent water from dripping.
These usually have one handle that is attached at the faucet base. It has a ball shape base which controls water volume and also mixes the hot and cold
How to repair
Doing your own faucet repair is tiresome; but with some experts training, you can easily do it. In fact, the hard thing is just finding the replacements of certain parts which you might get help from any store around you, because the tools used are different according to the type of the faucet. And since the types of faucets vary, there is one common way to clean them. The first priority is to take a close look at the faucet and find out where the leak is coming from. Then turn off the water supply from the valves. These valves are usually found below the sinks and if they dont work , shut it down from the source or from the water main meter box. Since there is water remaining in the pipes, open all the tanks to drain it away and also release the pressure. As you are working, you could probably drop something you dont want to go to the system so put a stopper in the sink. Some parts of the sink could have deteriorated due to the mineral deposits; such surfaces need to be cleaned thoroughly with an abrasive pad or cotton clothing. You can use vinegar to loosen the mineral deposits.
There may be some water holes which have been closed by the mineral parts. For this, use a sharp knife to clean them. Open the shut off valves and let the water flow freely as you let all the air out. Faucets parts are easily available in the hardware stores, but if you have a complicated faucet you may need to order. Since there are very many variations from the stores, it helps to know the type you are looking for or the model number. You may also carry with you the cartridge parts removed to the hardware store so you can compare with new ones.