Tools
Screwdriver, torque wrench or monkey wrench. You might also keep on hand a cloth towel to place within the teeth of the wrench so as not to damage any metal while working. Teflon tape is case the threads of the incoming-water pipes are a bit off and some water leaks.

Body
o The normal thing to do is place the new tap in the hole of the two-piece element you are going to remove. If your taps are separated, each operating independently, you must change the sink or cover up one of the holes.
o There are myriad models and colors of single-handle faucets. There are also many different prices to suit any kind of budget.
o With this kind of plumbing it is easier to save on water. And drips caused by wear and tear of old-fashioned rubber washers are a thing of the past.
o In case of a breakdown you have to change the entire device.

How they work
o It is a blending faucet that works with just one handle.
o It is very easy to use. A slight push upward increases the water pressure, and one downward eases it. These same movements serve to gradually open and close the flow of water.
o A slight movement to the left or right regulates the flow of hot or cold water. Or it makes lukewarm water come out. When the water pressure is low it is harder to regulate the temperature.
o Two ceramic disks inside the device block the flow of water or let it proceed gradually. The disks do not separate, but rather rotate over each other. This gradually lines up the water-flow sections.
o Other models do a similar task using a spherical cartridge with different openings which, when moved, allow hot and cold water to flow and mixes them.
o These simple mechanisms substitute the traditional water and allow for complete watertightness.
o There are models which allow you to set the temperature of the water beforehand.

Before beginning
o Before you start make sure the hot and cold water pipes are clean. If you have done remodeling work there may be remains of plaster, cement, caulking or soldering material. Let the water run freely. If necessary remove the faucets and let the water come right out of the pipes for a few minutes. Do this by opening and closing the stopcock quickly. Have a bucket or other receptacle ready so as not to flood the floor and cause other damage.
o After cleaning, turn off the main water switch. But if you have mains switches in the room where you are replacing the faucet, i.e. the kitchen or the bathroom, you may shut down just the one corresponding to the faucet. This way you can keep using water in the rest of the house.

How to install it the faucet
o Remove the old tap. Take it apart by loosening the screws under the sink.
o Now unscrew each of the rigid or flexible tubes or hoses that come out of each of the hot and cold water pipes. These will be located in the wall.
o Each of these two pipes will have a stopcock. Remember that you must close them if you have not shut down the mains for the whole house or the one for the room you are working in.
o In the hole left by the old faucet, install the new one. If the hole allows it, you can first attach the ends of the hot and cold water conduits to the base of the single-grip faucet. If this is not the case, you will have to screw them from underneath the sink.
o Now all you have to do is attach each of the flexible tubes to the hot and cold water pipes in the wall.
o In order to attach the faucet well to the bathroom or kitchen sink, you must screw it in tightly. Don't forget the plastic joints that will come with the faucet.
o Open the mains tap and check that the faucet works properly and that there are no leaks.