Best Flushing Toilets

Pressure Assist vs Gravity Flushing Toilets: What’s The Difference?

Pressure Assist Toilet (PAT) and Gravity Flushing toilet are two types of toilets that use different mechanisms for removing human waste. PAT uses a pressure pump to push the waste up, while Gravity Flush toilet uses gravity to pull it down. The difference in performance and power between these two types of toilets is proportional to their design and construction.

The Pressure Assist Toilet

A pressure assist flushing toilet is a toilet with an extra pump that moves water from the tank to the bowl. The pump does not run all the time, but only when the user presses a lever or touches a button on the tank. These toilets work very well for many users

The PAT consumes less water per flush, as it uses a pressurized water tank to do its job rather than relying on gravity alone. However, it requires the installation of a separate pump system in order to activate this mechanism. It is important to note that pressure assist toilets are designed with dual flush capability, which means they can be programmed to perform one or two flushes at a time.

Gravity Flushing Toilet

A gravity flushing toilet works by siphoning water from the tank into a bowl. The tank has an open pipe, called a vent (upper left), through which air can flow in or out freely. When you push the flush lever, the float drops and closes the vent. Water then fills the tank, raising the float with it. As this happens, water also fills up a curved pipe attached to the side of the bowl. This pipe is called an S-bend, because it looks like an S lying on its side.

Tanks for gravity flushing toilets are usually about six inches tall and three inches wide at the bottom. The S-bend is typically two inches high and one inch wide at its widest point. That’s all that needs to be bigger than normal to make sure that most of the water drains out of it after each flush.

The weight of all this water above the float creates suction that pulls water down through a hole in the bottom of the bowl and into a pipe leading to another hole near the bottom of the bowl, called an overflow tube.


The standard gravity flushing system has been around for centuries. It’s a simple design that has remained largely unchanged and is still the most common way of getting rid of waste in homes across the country.

The pressure assist flushing toilet system offers a more efficient way to get rid of waste with a less frequent need for maintenance. It offers all the same comfort benefits as a gravity flushing toilet, but will cost you more. The key difference between these two systems is that the pressure assist system uses water pressure to force waste out of the bowl and into your sewer system.

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