9 Types Of Toilet Flush Systems

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Whether you’re installing a new toilet flush mechanism, replacing a broken one, or trying to decide what kind of toilet to buy – one of the most important things to consider is the type of flush system the toilet uses. 

Flush toilets are toilets that, as the name suggests, flush out the toilet bowl contents through a drainpipe to a city sewer system or septic system, unlike waterless toilets or composting toilets that do not have a flushing system.

For decades, most toilets in the US used flapper-flush valves, however newer options including the siphon flush and pressure-assisted among others. 

Here are the most common toilet flushing mechanisms currently used in residential toilets. 

Common Types Of Toilet Flush Systems

Tank Fill Valve Flush System

Tank fill valve flush systems use a ballcock with a plunger which is a mechanism for filling water tanks. It’s basically a floating ball that is attached to a floating rod. The rod moves to activate the plunger in the ballcock’s body to allow and stop water from flowing to the tank.

Fluidmaster 400CRP14 Universal Toilet Fill Valve and Flapper Repair Kit, for 2-Inch Flush Valve Toilets
Fluidmaster 400CRP14 Universal Toilet Fill Valve (Image: Amazon)

Flapper-Flush Valve Flush System

This is a toilet flush valve that is opened and closed by a plate hinged at one side. This mechanism is called the Flapper, and it is usually made of plastic and soft rubber. The flapper is connected to a chain hanging down from the flush handle lever and is responsible for allowing and stopping water from flowing to the tank.

Siphon Flush Mechanism

This is a generic flushing system that uses a Bowl Siphon, a key mechanism molded into the bowl and is necessary to create a siphon using water to drain the toilet wastes from the bowl through the trapway and into the septic tank. Most siphon flush toilets use a lever to flush. This lever, when pushed, opens the flush valve and lets water flow into the bowl.

Rovtop Toilet Fill Valve, with Adjustable Quick Shut Off and Perfect Flush Anti-Siphon
Rovtop Toilet Fill Valve, Anti-Siphon (Image: Amazon.com)

Washdown Toilet

Washdown toilets are another generic flushing systems that, unlike siphon flush toilets, often have large trapways that are not meant to siphon water off the trap. Instead, they use the washdown method where water is forced into the bowl to push the waste down through the trap. Today, washdown toilets adopt dual-flush technology (read more of this later) and pave the way for modern flushing systems that are very popular in the market.

Pressure-Assisted Flush System

This is a powerful flushing system that uses pressurized air to force water into the bowl. This flushing system is excellent especially for large bowls like those being used in public toilets, which handle much more human excretions and foreign objects thrown in the bowl; these toilets need a powerful flushing system, thus, pressure-assisted flush systems are commonly used for them. The downside to this flush system is that it’s very noisy.

Vintage flush system
Vintage flush system | Photo Credit: Susann Mielke

Gravity Flush System

This may be the oldest type of flushing system, but it’s also the most popular in the market. Gravity flush systems apply water to make the flushing pressure, which then forces the contents from the tank and bowl into the trapway. There’s a siphoning action at the end of each flush which further cleanses the bowl, and given that there aren’t any additional mechanics involved, the gravity flush, unlike the pressure-assisted flush, is a quieter flushing system.

Double Cyclone Flush System

The double cyclone flushing system is one of the latest flushing systems that were introduced in the market. Pioneered by the known toilet brand Toto, double cyclone flushing systems use two nozzles supported by a propulsion system which allows more water to flow to pass through the tube and produces a more powerful siphoning action for a much more efficient flush.

Double cyclone flush systems are somewhat similar to gravity flush systems as they utilize some gravity flush mechanics to complete the flushing process.

Dual Flush System

Dual flush systems are also one of the latest flushing systems in the market and are quickly gaining popularity. With dual flush toilets, users can choose between a partial flush and a full flush. This provides a bit of a solution to some water consumption arguments as it can potentially save consumers tons of water.

A full flush uses around a gallon and half of water per flush while a partial flash uses less than a gallon of water, which is ideal if the bowl contains only urine. Flushing is done with just the push of a button and users experience far fewer issues with this toilet flushing system than any of the others in this list.

FlushSaver 3" DRAIN STANDARD LEVER HANDLE Dual-Flush Deluxe DIY Conversion Kit - FITS STANDARD 3" DRAIN TWO PIECE TOILETS. Converts standard toilets into efficient dual-flush systems.
FlushSaver Dual-Flush System (Image: Amazon.com)

Rear Flush Toilet System

Rear flush toilet systems use a different kind of toilet bowl. It has more to do with bathroom space convenience rather than flushing. However, this flush toilet system deserves to be on this list since it is widely used mainly in European countries. Rear flush toilet systems offer more flushing power than conventional flush toilet systems, and this is often because of pressure-assisted devices that add more power with every flush.

Rear flush toilets are more compact compared to floor flush toilets. They use very minimal bathroom space which is why many consumers prefer this flush toilet type.

Ballcock float type. Image Source

These are only some of the many toilet flushing systems that are available in the market, and it’s safe to assume that a lot more will be introduced to us as our technologies progress further. Indeed, some toilet flushing systems are far superior to others, but regardless of the flush toilet system type we’re using, these flush systems were invented to make our lives more convenient.

What flushing system do you use at home? Feel free to share your comments below!