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9 Types of Toilet Flush Systems: Pros and Cons

Let’s flush things out.

We are fortunate that more people have access to running water and modern plumbing than ever before. One of the most important of these innovations is a flushing toilet, which removes waste from your home in seconds.

We flush our toilets multiple times per day but you might not give much thought to how they actually work. Although they are all designed for the same purpose, there are several different flushing systems used in toilets.

In this article, we will explore some of the current most popular types of toilet flush systems. These range from a standard ballcock flush commonly used in homes to the sealed vacuum flush found on airplanes.

Key Takeaways

  • Ballcock Flush System: Common type using a floating ball and plunger for water control.
  • Siphon Flush: Popular in the US, creates a vacuum seal and gurgling sound when flushing.
  • Flapper-Flush Valve: Similar to ballcock flush but uses a flapper instead of a ball.
  • Gravity Flush System: An older system that uses gravity to create flushing pressure.

Types of Toilet Flush Systems

Ballcock Flush System

The ballcock flush system is one of the most commonly used types. It uses a ballcock and a plunger that fills the toilet’s water tank to a specific level.

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

The ballcock depends on the water level — if there is insufficient water, it won’t function properly. There can also be issues if the shut-off valve is set too high. This will mean the water won’t shut off, allowing it to flow into the overflow tube.


  • Easily replaced
  • Works effectively


  • Prone to failure

Siphon Flush

Siphonic flush systems are very common in the United States. They are easy to recognize as the toilet’s water level will rise quickly before the toilet flushes.

There is also a signature gurgling sound caused by the vacuum seal being broken. These flushes are activated by a button at the top of the tank that opens the flush valve, allowing the water through the bowl.

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.


  • Leaves bowl cleaner
  • Powerful flush


  • Prone to clogs

Flapper-Flush Valve

A flapper-flush system works similarly to a ballcock flush, but it is controlled by a flapper rather than a ball.

The flapper is filled with air and floats. When you trigger the flush lever on the tank, 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 falls back into its seat. This allows the tank to refill, readying it for the next flush. There are newer versions of this type that offer dual flushing — one type for solids and one for fluids.


  • Simple system
  • Easy to maintain


  • Can be slow to refill

Pressure-Assisted System

Pressure-assisted systems rely on water pressure instead of gravity, which is used by most toilets.

These are commonly used in commercial settings as they provide a powerful flush that prevents clogging. This also makes them easy to maintain and leaves the bowl cleaner.

Presure-assisted flushes are activated when you press a button or lever, which releases the air pressure that builds as water enters the tank. When the air pressure is released, the water moves down with great force, removing the waste from the toilet.


  • Keeps the bowl clean
  • Very powerful flush


  • Loud flush

Gravity Flush System

The gravity flush system is one of the oldest systems but is still popular in some settings. It releases water that is elevated above the bowl, creating flush pressure when it is released. The pressure then forces the waste from the bowl and into the trapway.

After each flush, a siphonic effect clears the bowl before refilling it — this ensures nothing becomes trapped. As there are no complicated mechanisms, it is easy to perform repairs and replacements. There also won’t be any loud noises because gravity is the primary force at work.


  • Quiet
  • Powerful


  • Clogs more easily than pressure-assisted flushes

Double Cyclone System

The double cyclone system is one of the newest flush types. Originally created by the Toto toilet company, it is becoming increasingly popular.

It uses two nozzles that are supported by a propulsion system, allowing more water through the tube. As a result, it creates a very powerful siphoning action with a more efficient flush.

Despite its name, a double cyclone system is actually relatively simple. It utilizes some gravity flush mechanisms during the process.


  • Powerful while using less water
  • Simple mechanism


  • Can be difficult to find replacement parts

Dual System

Dual flush systems are designed to remove solids and liquids differently, depending on how you press their controls. They usually have separate buttons for solids and liquids – but some have a single button that can be pressed on one side or the other.

They are designed to reduce water waste by only using the necessary amount for the type of waste in your toilet. Fluids don’t require as much water to be flushed effectively, but more force is needed to push solid waste down the toilet’s trapway.


  • Reduces water waste
  • Ideal if you have a limited water supply


  • Not very common in the United States

Washdown Toilet

Washdown toilets are mostly seen in Europe and rarely in the US. They are often compared to a regular siphon toilet but have a bigger trapway, making it easier for water and waste to leave your bowl.

There are no complicated valves or floating balls in this system. It uses the water’s weight and gravity to flush the toilet. This also means it operates quietly.


  • Generally clog-free
  • Flushes quickly


  • Can leave skid marks in your toilet

Rear Toilet Flush System

Rear toilet flush systems are less common and are generally used in tight spaces where there is no room to install a traditional cistern. Although this means a more complicated installation, they are ideal for achieving a sleek, minimalist look as the toilet’s plumbing and fixtures are concealed.

The main issue is that these toilets are fitted onto the wall and can become loose with time, causing leaks. This means they require extra maintenance and the process is more complicated.


  • Minimalist modern look
  • Powerful flush


  • Installation and maintenance are more complicated


Which Toilet Flush System Is the Best?

Each type of toilet flush system has pros and cons. Some systems utilize siphonic action, where water is rapidly siphoned from the bowl into the siphon tube and down into the drain.

Others use a ballcock mechanism, where a ball attached to an arm moves when the water levels changes and automatically seals the flow of water when it reaches a certain point.

Some systems rely solely on gravity to flush the toilet, using water from your home’s main supply. Gravity toilets are quiet, which is helpful if you are trying to avoid waking your housemates. Some toilets have more advanced systems, such as dual cyclone flushing technology that utilizes centrifugal force to effectively remove waste from the bowl.

Finding the right flush system isn’t only about removing waste as quickly as possible; it should also refill quickly if you live in a busy household.

Can I Make My Toilet Flush Stronger?

If you often notice waste being left in your toilet after you flush, there could be an issue with your system. Before you buy a replacement, there might be a problem that is relatively easy to fix. Here are some of the most common issues and how to fix them:

  • Clogs: An easy way to check if something is clogging your system is by pouring a gallon of water into the bowl. Flush it and, if it drains slowly, you might be dealing with a partial clog. You can use a plunger or a snake, but there are some other methods to unclog a toilet without a plunger.
  • Vinegar soak: To use this method, you need to open the lid to the tank and remove the fill hose. Place a funnel into the overflow tube and pour in four cups of white vinegar. Leave it for a couple of hours, then put everything back into place and flush the toilet. The acidity in vinegar effectively breaks down grime and clogs (1).
  • Clogged rims: The water that comes from the toilet’s rim helps to keep the bowl clean. However, these rims can also become clogged. When cleaning your toilet, run the brush along the inside of the rim to remove any possible blockages (2).
  • Replacing a pipe: If none of the previous methods work, you will need to make some more drastic changes. Pipes that are too small for your toilet are a common cause of blockages and they might need replacing or upgrading. Unless you are an experienced plumber, this is a task that is best left to a professional.

What Is a Class 5 Flushing System?

A class 5 flushing system is a mechanical sewer flushing mechanism that clears blockages and other buildups from the sewer lines.

This system works by pumping water at high pressure through a bulkhead assembly, which is typically mounted at the top of the main vertical sewer pipe.

The flush dislodges any material accumulated inside the sewer pipe,removing it and preventing foul odors from forming.

As a class 5 system uses clean water rather than potent chemicals like many other sewage cleaning mechanisms, it is also a more environmentally-friendly solution.

How Often Should You Replace Your Toilet Flush System?

The lifespan of a toilet flush system is influenced by several factors. In general, you should replace your toilet flushing system every six or seven years to ensure it continues to function effectively and to prevent potential leaks and other issues.

Replacing your toilet flush system when required will ensure your plumbing system is efficient and that you won’t waste money by using more water than necessary.

Which Is Better: Single Flush or Dual Flush?

Some people prefer a single-flush toilet, which uses a single powerful flush to remove all waste in one go. Others prefer a dual flush toilet, which allows you to use more or less water depending on whether you need to flush solid or liquid waste.

Both toilet types have their advantages but dual-flush toilets are more efficient and cost-effective than single-flush toilets. They could reduce your toilet’s water usage by as much as 40% while still removing waste effectively.

Dual-flush toilets are less common than single-flush models, so you might need to spend some extra money to get one.

What Is Better: Siphon Jet or Gravity Flush?

Both siphon jet and gravity flush toilets have advantages and drawbacks, so it is largely a matter of personal preference and what type works best for your home.

Gravity flush toilets are more affordable as they use less water per flush than siphon jet toilets. However, water can splash out of the bowl if they are not properly sealed around the rim, and they are not ideal for larger bathrooms.

Siphon jet toilets usually provide a more powerful flush and are less likely to clog than gravity flush toilets. This is why they are often used in commercial and public bathrooms.

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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.