How does a toilet tank work?

Answer 1

Water is allowed in from the cold supply line via a fill valve which close when required amount is in tank. Most tanks have a rubber 'flapper' valve over the outlet. When this is raised (as you press the lever) , the water in tank flows to the bowl and flushes it.

Answer 2

In the base of the toilet, the drain is shaped like an upside down U. When you flush, the water in the bowl rises. Water seeks it own level and when it is higher than the top of the upside down U, it goes over the top and causes a suction or syphon that draws the rest of the water in the bowl after it. until it sucks air and breaks the syphon.

Answer 3

A toilet works with water pressure.