Informational Guide

How Does A Toilet Work?

In this detailed guide, we have gathered together some must-know information to help you to understand how a typical toilet works.

by Ian Haynes

Do you know that an average person spends a total of one year sitting on a toilet seat during their lifetime? Surprised? The truth is a toilet is the most common plumbing fixture in our households, yet we are willing to bet that few of us have ever thought about how a toilet works.

In this detailed guide, we have gathered together some must-know information to help you to understand how a typical toilet works.

A typical toilet comprises over 40 parts that work together in union to help you take care of business.

In fact, many consider the toilet as a modern engineering wonder.

Let’s take a closer look at a toilet and its parts to understand how it works.

toilet diagram

A toilet has two basic parts; the tank, which is filled with approximately 2 gallons of water to be used for flushing, and a bowl which is used to collect and dispose of the waste into the drainage system.

As well as the tank and bowl, your toilet consists of:

Handle or Push Button

The easiest part to understand is the flush mechanism. You use this to flush the toilet by pushing the handle/lever, which lifts the chain inside the tank and triggers the flush valve to open up.

This allows water to move quickly from the tank to the bowl, which pushes the bowl’s contents through the drainage system.

Flapper or Tank ball

This is usually made of rubber and sits on the flush valve opening. When this rubber plug lifts, water shoots down into the bowl to dispose of waste through an S-shaped drain. When the tank empties, the valve reseals, allowing the tank to refill.

Fill Valve or Ballcock

The fill valve is an essential component of the toilet. After flushing, when the tank is empty, the fill valve is released, allowing the tank to refill from the main water supply. Typically, water flows from the base of the valve and upwards till it reaches the overflow tube.

Shutoff Valve

Another incredibly important part of a toilet, the shutoff valve, is used to shut off the toilet tank's water supply.

Top tip: Always know where your shutoff valve is to your toilet so you can turn off the water supply in case of leaks or damage.

Overflow Tube

The overflow tube stops water from overflowing from the tank in case of a malfunction in the water supply valve.

Supply Tube

Made of vinyl, plastic, or steel mesh, this is a pipe that connects the main water supply to the shutoff valve.

Lift Chain

The lift chain is connected to the flush mechanism and the flapper or tank ball. It opens up the flush valve so that water can flow into the toilet bowl. The lift chain runs vertically from the tank handle to the bottom of the tank.

Most Common Types of Toilets

Flush Toilets

Flush toilets are the most popular and common type of toilets used in homes, offices, and public spaces.

Flush toilets use water to flush waste into the main drainage system. Flush toilets use laws of pressure and gravity to dispose of the waste in a very efficient manner, disposing of waste in a few seconds.

Flush toilets come in various designs, shapes, and sizes and can be single-flush, dual-flush, or even no-touch.

Macerating Toilets

Macerating toilets are very different from traditional flush toilets. These toilets convert human waste into a liquid state through a pair of grinding blades. This liquid is then pumped out through a drainage pipe and into the main sewage system.

Since macerating toilets don’t use gravity to function, they are ideal for installing in places where a traditional toilet may not be suitable, such as those without a typical drainage system.

Another advantage of macerating toilets is that they are compact and can be installed in small tight spaces rather conveniently.

Vacuum Toilets

Vacuum toilets are found inside planes, boats, and sometimes homes.

These toilets, as the name suggests, use a vacuum to dispose of human waste. The vacuum is very powerful and therefore uses little to no water. When flushed, this opens up a valve to suck the waste out through the vacuum.

Vacuum toilets are ideal for homes that may be isolated from the main water supply, such as remote log cabins.

Composting Toilets

Composting toilets are environmental-friendly toilets that decompose waste rather than just disposing of it. They separate liquid and solid waste and then mix them with microbes or peat moss to decompose.

Composting toilets are used by campers in outdoor locations, convenient and portable to have all the comforts of home while minimizing water consumption. Some people even use their composted waste in their gardens.

Despite what you may think, composting toilets are odorless, showcasing modern design and engineering to create a very convenient alternative to the typical plumbed toilet.

Cassette Toilets

Cassette toilets are used inside RV’s or caravans to dispose of waste.

In a cassette toilet, the toilet system is fixed. However, the waste tank is detachable which can be emptied anywhere. The problem with these toilets is that the tank capacity is limited, so you might need to empty them frequently.

Sea or Marine toilets

As the name suggests, Marine toilets are used in sea vehicles such as boats, submarines, and yachts.

Since the sea can be rough with splashing waves and strong winds, the traditional toilet is not suitable as water spills would be commonplace.

Marine toilets work by keeping the bowl dry until flushed. At that point, water will enter the bowl and carry away the waste into a holding tank beneath the toilet. The bowl will be completely empty until the next use.

Marine or sea toilets can be electric or hand-powered and come in a variety of shapes and designs.


How Does a Toilet Work? (Step-By-Step)

  • Step 1:
    The first step is pressing or pushing the flush handle/button. When this happens, the lift chain attached to the handle pulls up the flapper sitting on the flush valve opening. This releases the water from the tank and into the bowl through tiny inlets around the rim of the bowl and from a short pipe with high pressure. This all happens in a matter of seconds
  • Step 2:
    With so much water entering the bowl at once, a small torrent is created, and all the water and waste are forced by gravity to leave the bowl and into the main drainage pipe. The bowl is now free of any dirty water or waste. Since the drain pipe connecting the bowl to the main sewage line is an 'S' shape, some of the water from flushing is left behind in the bowl. The 'S' bend design helps accelerate the flushing process and stops bad smells from filling your bathroom.
  • Step 3:
    Now that the tank is empty, the flapper moves back to its place, closing the flush valve opening. The float ball drops to the bottom of the tank causing the water supply valve to open. Freshwater now fills the tank via the fill valve. When the float ball rises, it shuts off the water supply valve once the water reaches the tank’s max limit. The tank is ready now for the next person to use.

People Also Ask (FAQs)

How does a toilet fill with water?

The toilet tank has a fill valve that is connected to the main water supply. When the tank is empty, a float ball inside the tank drops, which triggers the water to fill the tank. As the water level rises, so does the float ball, stopping the inflow when it reaches the max height.

How can I unclog my toilet?

Use a special toilet plunger to unclog. You can also use a unique drain snake tool called a toilet auger, for more serious blockages.

How can I fix a loose flush handle?

Over time, your flush handle can loosen up or even disconnect from the tank.

To fix this, you first need to determine whether the lift chain has become detached or whether the handle is just loose.

You can reattach the lift chain easily by reaching inside of the tank and reattaching the separated components. To tighten, you can rotate the handle mounting nut in the counterclockwise direction to tighten it up from inside the tank.

Why is the toilet not flushing strongly?

If your toilet has a weak flush, it’s usually for two reasons;

  1. 1
    Something is blocking the inlet pipe, or it has become worn or damaged.
  2. 2
    The maximum water level setting in the tank is set too low.

You can follow this YouTube video for tips on how to fix a weak flushing toilet.

Why does my toilet run continuously?

There are a few reasons why your toilet could constantly be running.

  1. 1
    Leaking flapper
  2. 2
    Malfunctioning refill tube
  3. 3
    Misaligned or malfunctioning float ball
  4. 4
    Wrong length of the flush valve chain
  5. 5
    Worn gasket
  6. 6
    Stuck handle/button

We’ve written a full troubleshooting guide on how to fix a running toilet to help solve your toilet troubles.

Why does my toilet handle get stuck?

Often, a stuck toilet handle can be fixed by hand. You can use an adjustable wrench to loosen up the nut from inside the tank in more serious cases. This is relatively easy to do, and you don’t need a plumber to help.


Toilets are an integral part of our living space, whether on road, sea, air, or land. Toilets are made up of many small components that work together for easy waste disposal, but these components can malfunction anytime.

Having a basic understanding of how a toilet works can help you fix the most common problems yourself without calling in a plumber.

Ian Haynes is an expert writer who has successfully deployed over 500 plumbing pages and other related content. He has an excellent understanding of home plumbing issues and translates his experiences via Plumbing Lab so readers can have a better understanding of common household problems. Outside of his work, Ian likes exploring Brooklyn with his Labrador.