Water Tank

• The apparent lack of a tank is the first thing most people notice about a wall-mounted toilet. In fact, wall-hung toilets use the same gravity flush system as a normal commode. The slender water tank is mounted on a sturdy metal frame that connects to studs in the wall, which is then finished around the various pipes and controls for the toilet. To prevent tank freeze-up, wall hung toilets should not be placed on exterior walls in cold climates.
  
  

Bowl Mounting

• The same metal frame that holds the water tank also supports the bowl, which does not touch the floor. Two strong, threaded rods screw into holes in the frame at a convenient height. The wall is finished around them, and the flat-backed bowl assembly slides over the rods and is bolted into place. Adhesive on the back of the bowl lends an additional layer of support, and a line of caulk around the outside prevents moisture from getting into any crevices between the bowl and the wall.
  
  

Flush Mechanism

• Because the tank is hidden, wall-hung toilets have no lever for flushing. Instead, a button on the wall above the bowl connects by means of an actuator to a valve in the inlet pipe inside the wall and above the water tank. Some models have two buttons controlling two flush modes; one using more water and one using less. These different flush modes, labelled "full flush" and "low flush," are used as a water-saving measure.
  
  

Drainage Pipe

• In a normal toilet, the drainage pipe leads down through the floor at the base of the bowl and into the home's drain system. In a wall-mounted toilet, the drainage pipe comes out of the back of the bowl near the bottom, joining up with the drain system via a pipe in the wall. This pipe travels down through the wall's base plate in most cases, though it is possible to hook into a horizontal drain pipe in the wall, as well.