What is the engineering behind toilets?

Flush toilets are undoubtedly one of the fancy, widely used inventions. Let us go step by step about the functioning.



  • Once the flush handle is pressed, the flush valve is lifted. The valve allows the stored tank water into the bowl.

  • Water rushes through the valve and as well as from the holes in the rim. So that the bowl will get a wash along with flushing the contents away.

  • The bowl is now filled with enough water and gravity forces water to move through the S-shaped siphon tube, causing it to overflow the top of the tube.

  • Water rushing over the top of the siphon tube creates suction, evacuating the waste and water from the bowl. As the water is pulled from the bowl, air enters the tube which ends the siphon effect and the flush.

  • The mechanism is built in such a way that there is some water remains at the bottom of the bowl always, which improves hygiene and prevents bad odors coming from the drain pipe.

  • Once the tank is empty, the filler float falls downward tilting a lever.

  • The lever opens the fill valve which is connected to the water supply line. Pressurized water flows in which refills the tank and pushing the filler float back up again.

  • When the float reaches the correct level, the filler valve gets closed. This stops the water supply and the toilet is ready to flush again.