Handles

• Faucets have handles to operate the water flow. This handle moves a cylinder inside of a cartridge that adjusts the flow of water into the spout. Some faucets have one single handle to control both hot and cold water. The handle operates the valve system that controls the water into the faucet. This valve system is either a disc, cartridge or stem-and-valve system. Today, most faucets use a cartridge that contains two rotating discs with inlets that align to allow water through to the spout. The older stem faucets have a valve that screws down into a seat to turn off water pressure. Disc faucets also use a compression style valve to shut off water.
  
  

Spout

• The faucet spout is another common part. This spout is typically made from metal like brass, copper or stainless steel. It is shaped like a small, curved bell and is open at one end. The spout connects both the hot and cold water inlets running to the faucet. When the handle turns the water on, the water rushes through the cartridge and into the spout, where it mixes and becomes temperate. By adjusting the handles, you adjust the water flow from each side, allowing both hot and cold water to mix inside the spout. The spout also has an aerator, a mesh screen that introduces air into the water stream. This part screws onto the end of the spout.
  
  

Base

• Faucets have bases with a series of shafts. The shafts run down from the handles of the faucet and mounting hardware threads onto the shafts to secure the faucet to the counter top. If a faucet has a single, one-piece handle on a single base, it mounts directly into a single hole in your sink or counter. If the sink or counter has two holes drilled for a center set faucet, the single-handle faucet uses a base to cover the two additional holes. Roman tubs and widespread faucets that have individual handles and spouts have no singular base plate. Each installs in its own hole in the sink.
  
  

Single Handle Faucets vs. Double Handle Faucets

• A single-handle faucet has only one handle to operate the hot and cold water coming into the faucet. This handle connects to the cartridge inside the faucet body, and when turned it aligns the inlet holes to allow one, both or none of the water inlets to open. This action allows more or less hot and cold water into the faucet's spout. It is important to note that two handle faucets have a separate cartridge or stem valve for each handle; one simply opens to allow hot or cold water into the spout, depending on which one is operated.