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Types of Toilet Flush Systems

Let’s flush things out.

We all know that our toilet flushes, but do you know which system your toilet uses? Many homeowners don’t give it much thought. However, there are actually many types of toilet flush systems.

Nowadays, new types of systems include the automatic flush and sealed vacuum flush. However, these are generally found in different settings, such as airplanes.

Types of Toilet Flush Systems

Ballcock Flush System

The ballcock flush system is one of the most commonly used flushes. It uses a ballcock along with a plunger that fills the water tank of the toilet.

A ballcock is a floating ball attached to a rod. As the rod moves, it activates the plunger, which allows water to either fill or empty the tank.

The ballcock is very dependent on the water level — if there’s too little water, it won’t function properly.

Another fault can also be due to the shut off valve being set too high. As a result, the water fails to shut off, causing it to run into the overflow tube.


  • Easy replacements.
  • Works effectively.


  • Prone to failure.

Siphon Flush

Siphonic flush systems are very common in the US.

As you flush, you’ll notice the water rising rapidly in the bowl before flushing out.

You’ll also hear the iconic gurgling sound caused by the vacuum seal being broken.

It’s triggered by a button at the top of the tank, which then opens the flush valve, allowing the water through the bowl.


  • Cleaner bowl.
  • Powerful flush.


  • Prone to clogs.

Take Note

A common problem with this type of flush system is the trapway. The trapway is long and narrow, so it’s prone to clogging. It’s recommended to keep a plunger close at hand in case a clog was to happen.

Flapper-Flush Valve

This type of flush system works similarly to the ballcock, but it consists of a flapper, not a ball.

The flapper is filled with air and floats once you trigger the flush by the lever on the tank. Then, the flapper is pulled out of its seat by a chain and allows water to flow from the tank to the bowl.

As the water level drops, the flapper won’t be able to float and fall back into its seat. This will allow the tank to refill, preparing for the next flush. Newer versions of this type are widely available that include dual flushing — one for solids and one for fluids.


  • Simple system.
  • Easy to maintain.


  • Can be slow to fill.

Pressure-Assisted System

Pressure-assisted systems rely on pressure as opposed to gravitational force like most systems.

It’s commonly used in commercial settings because of its powerful flush that’s unlikely to clog. Because it’s less prone to clogs, it’s also very easily maintained and keeps the bowl cleaner.

It’s triggered as you either press a button or lever, which releases air pressure that’s been building as water enters the tank. As the air pressure is released, the water is pulled down with great force, clearing the waste in one go.


  • Keeps the bowl clean.
  • Very strong flush.


  • Noisy.

Gravity Flush System

The gravity flush system is some of the oldest systems used. It works simply by applying water that causes flush-pressure. The pressure then forces the content out of the bowl and into the trapway.

After each flush, there’s a siphonic effect that clears the bowl before refilling it — this helps to ensure nothing becomes trapped.

There are no complicated mechanisms in this system so it’s easy to do repairs and replacements. In addition, because it’s a gravity-forced flush, there are no loud sounds such as pressure flush systems.


  • Quiet.
  • Strong.


  • Can clog.

Double Cyclone System

One of the newer flushing systems is the double cyclone system. Originally created by the toilet company Toto, it’s becoming more and more popular.

It uses two nozzles that are backed by a propulsion system — this system allows more water to pass through the tube. Consequently, it creates a very powerful siphoning action with a more efficient flush.

Despite being a double cyclone flush system, it’s actually quite a basic mechanism. It uses some gravity flush mechanisms within the process.


  • Powerful while using less water.
  • Simple mechanism.


  • May be difficult to find replacement parts.

Dual System

Dual flush systems are designed to handle solids and liquids differently, depending on what you press. Some systems have two different buttons — one marked for solids and one for liquids. Others have one button that you either press to one side or the other.

The point of dual flush systems is to preserve water by suiting it to the waste in the bowl. Liquids don’t require as much force or water to be flushed. Solid wastes, in comparison, need more force to be pushed down the trapway.


  • Better for the environment.
  • Excellent in areas with short water supply.


  • Not as common in the US.

Washdown Toilet

Washdown toilets are mostly seen in Europe and rarely in the US. These are often compared to a regular siphon toilet. However, they have a bigger trapway, which makes it easier for water and waste to escape.

There are no complicated valves or floating balls in this system. All it uses is the weight and gravitational water flow to flush-out the toilet. As a result, all waste is pushed out of the bowl by the high pressure of the gushing water.


  • Relatively clog-free.
  • Flushes quickly.


  • Causes skid marks in the bowl.

Rear Toilet Flush System

Rear toilet flush systems are less common, but generally used in more compromised spaces.

This system is often used in settings where the toilet doesn’t have a tank.

It can also be more sleek-looking since all plumbings and fixtures are hidden.


  • Looks modern.
  • Powerful flush.


  • Requires readjustments and regular maintenance.

Keep In Mind

Leaks are likely to happen, mainly due to the toilet being less stable than floor toilets. They’re bolted directly onto the wall and can become loose over time. Consequently, these types of toilets and flush systems require more maintenance and readjustments as well as replacements.

What Is the Best Toilet Flush System?

What type of flush system is the best depends on your needs and your bathroom setup. The point of the entire flush process is to get the bowl content from point A to point B. What we like to look for in a good flush system is how powerful it is, but also how quickly it recovers.

Some systems require a significant amount of time to refill after a flush, which can cause some trouble in a busy home. A noisy flush can also become quite annoying — this is often found in pressurized systems. We like to go for gravity-forced systems due to their quietness and effectiveness.

Can I Make My Toilet Flush Stronger?

If you often notice your flush isn’t getting rid of everything, there could be a problem. You can easily improve the flush of your toilet, but first, you must figure out what is causing it to be slow or less powerful. Here are different methods to try out:

  • Clogs: A quick way to see if something is clogging your system is by pouring 1 gallon of water into the bowl. As you flush, check to see if it struggles, then you’re likely dealing with a partial clog. Use a plunger, a snake, or some other way to unclog a toilet without a plunger
  • Vinegar soak: For this method, you need to open the lid to the tank and remove the fill hose. Place a funnel carefully into the overflow tube and fill it with 4 cups of white vinegar. Leave it for a couple of hours and then put everything back into place and flush the toilet. The acidity in vinegar works effectively at resolving grime and clogs (1).
  • Clogged rims: The water that comes out of the rims helps to keep the bowl clean. However, these can get clogged. As you’re cleaning your toilet, run the brush along the inside of the rim to remove anything that could be clogging the way (2).
  • Replacing a pipe: If none of the above are working, you’ll need to make some more drastic changes. There might be an old pipe that’s causing a lack of flush-power. This needs to be changed. Changing pipes can be a dreaded task if you’re unfamiliar, so you might want to call for some professional help.

Flushing the System

There are many different types of toilet flush systems; now you may have learned something new. The point of flush systems is to get the waste out of the bowl while keeping it clean. Some flush systems can be quite noisy, while others are very quiet.

When choosing a flush system for you, consider how powerful it is as well as how quickly it recovers. Slow recovery time can result in a clogged bowl, especially in a public setting or a busy family home.

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About the Author

Peter Gray

Peter has been a homeowner for 35+ years and has always done his own repair and improvement tasks. As a retired plumber, Peter now spends his time teaching others how they can fix leaks, replace faucets, and make home improvements on a budget.