How does a toilet flush system work?

Hiding under the lid of your toilet tank are several key parts that are crucial to make your toilet flush. These are:

• The toilet siphon – a one-piece or two-piece unit that contains a pipe, pull handle and a plastic flapper valve (which releases clean water into your toilet.)
• The flush valve

• The refill valve

These pieces are connected in perfect order to make your toilet flush. Here’s how it works:

1. When the flush handle is pressed, it pulls a chain connected to a flapper.
2. The flapper lifts and releases the tank water down the flush valve into the toilet bowl.
3. The pressure of the water pushes waste over the trap at the bottom of the bowl and into the main drain.
4. Once the tank is empty the flapper closes and forms a seal in the tank.
5. The water is then refilled in the tank from the main supply until it hits the float.
6. The float will rise with the water and shut the valve off stopping the water from flowing in once it has reached the fill line.

Behind the simple flush, your toilet cistern is working hard to clear unwanted waste away. After a while, the inside of your toilet tank can develop stains and grime which can spread throughout your toilet and reduce the efficiency of the mechanisms within the tank. You can read our guide on how to clean a toilet tank for more cleaning tips with Harpic.