How Does a Toilet Work?

A person is flushing a modern day toilet by pressing a button on the top of the tank with the words, how does a toilet work?

Children and pets have a fascination with toilets. As adults, we know that the modern toilet is a common item that is now seen more as a necessity than a luxury. They help keep our homes clean, give us some privacy, and help prevent diseases that were common back in the olden days. While many of us have lost our fascination with the mysteries of the modern toilet, a lot of people wish they knew how it worked when plumbing issues begin to arise. This article allows homeowners to understand exactly how their toilet works so that they may be able to spot and identify, a potential problem.

Parts of a Toilet

In order to better understand how a toilet works, you need to be familiar with all of its working parts. Here is a quick run-through about the different parts of your toilet.


The tank is the back part of the toilet that is used to hold the water for flushing your toilet. It also houses many of the working parts of your toilet, such as the fill valve. The tank itself doesn’t break very often but sometimes the lid may need to be replaced if it becomes cracked or damaged.

Tank Lever

This lever is attached to the handle of your toilet. When you flush, the handle forces the trip lever to open up the flush valve, which allows the water to wash down into the bowl.

Fill Valve

The fill valve controls the water supply to the tank. Its job is to communicate with the float ball and chain, so it knows when to turn the water off. If there is a problem with the fill valve and the water just continuously runs, you can always manually turn it off. You can find the fill valve on the back of the water pipes, it is the twist handle.

Flush Valve

The flush valve allows the water into the bowl of the toilet, to create enough water pressure to send its contents down the drain. It is the part in the tank that opens as soon as the handle is pushed.


The flapper is lifted by the tank lever which causes it to make the suction which forces the flush valve to open. Without this essential piece, your toilet would not have the pressure necessary to pull the contents into the drain and away from the home.

Supply and Overflow Tube

Connected to the stop valve, the supply tube takes the water from the main water line to a refill tube, which is used to refill the tank once the toilet is flushed. The overflow tube stops the water from running over when your toilet is clogged or there is another problem. It gives an escape to the water, allowing it to fill up the tube instead of your floor.


The bowl is the part of the toilet where your waste is collected, along with the water that will eventually accompany it down the drain.

Steps of Toilet Operation

A white toilet with a green wallNow that you are familiar with the different parts of the toilet, you will be able to better understand how it works. Once you flush, the fill valve sends water into the tank and stays on until the tank completely refills. This is why when an essential part of the toilet, such as the flapper, is allowing water to escape, the water continuously runs. It is trying to maintain the needed water level in order to allow the toilet to flush after the next use.

When the toilet is flushed, the flapper which sits on top of the flush valve is opened by a chain. This allows for the water to exit the tank and into the bowl. The water pressure coming from the water entering the bowl forces the water and waste into the drain. Once this is done, the water continues to run until the tank is refilled with water and the process is ready to start all over again.

If you have read through this and started to wonder why your toilet is refilling so slowly, or feel that there is a problem with your plumbing, do not hesitate to call HEB Plumbing and Sprinkler Services. Our expert plumbers will be able to help you solve your problem quickly, by identifying the source and coming up with a solution. No matter how big the problem, you can be sure the HEB Plumbing and Sprinklers has your back.