What Is a Pressure-Assisted Toilet?

Upgrade the flushing power in your home by adding a pressure-assisted toilet.

Pressure-assisted toilet with removed tank cover showing plastic tank

The Spruce / Kevin Norris

Most residential toilets—and even many commercial toilets—are standard gravity-flow models that can range from old, inefficient toilets that use up to 5 gallons of water per flush to newer toilets that only use about 1.6 gallons per flush (GPF). However, these more efficient gravity-flow toilets can lack the power necessary to fully flush waste, so if you regularly have problems with flushing power, a pressure-assisted toilet may be the best option. But what is a pressure-assisted toilet? Pressure-assisted toilets are both efficient and powerful, ensuring that you don't have to sacrifice on the water bill just to have a functioning bathroom.

This style of toilet has an airtight plastic tank inside the porcelain tank where the water is stored. The toilet uses both water and pressurized air to increase the velocity of the flushing water. It generates a powerful flush, while only using about 1.1 to 1.4 GPF. Additionally, the increased velocity of the water helps to break up any larger waste so the toilet doesn't require a larger trapway to function effectively. Read on to find out more about pressure-assisted toilets, how they work, and why these powerful bathroom fixtures are beneficial.


Click Play to Learn How Pressure-Assisted Toilets Work

How Pressure-Assisted Toilets Work

A typical residential toilet will have a large porcelain tank that fills with water and a bowl that acts as both a seat for the user and a water-filled collection point. When the toilet is flushed, a flapper lifts off of the flush valve, allowing gravity to force the water from the tank down into the bowl and push any waste into the drainpipe. A pressure-assisted toilet takes this system a step further by having an airtight plastic tank inside the large porcelain tank in order to improve the flushing power.

The airtight plastic tank fills with water between flushes, but it's designed to trap air inside the tank, increasing the air pressure as more water fills the tank. When the toilet is ready to flush, it uses the built-up air pressure to explosively force the water from the tank into the bowl at a much higher velocity than a gravity-flow toilet. Despite the increased power, these toilets actually use less water per flush than a gravity-flow toilet and don't require the trapway to be increased in size because larger waste is broken up by the force and velocity of the water.

Increase Flushing Power, Not Water Consumption

One of the main benefits of switching to a pressure-assisted toilet is that these plumbing fixtures have greatly improved flushing power without increasing the amount of water used per flush. In fact, pressure-assisted toilets typically save a household about 0.2 to 0.5 gallons per flush, or 4,000 gallons per year, reducing the cost of your water bills and promoting water conservation efforts. On average, newer gravity-flow toilets will use about 1.6 GPF.

Using less water may seem like a bad idea, but by increasing the velocity of the water, pressure-assisted toilets will typically only use about 1.1 to 1.4 GPF. Yet, they can flush with more power than a standard gravity-flow toilet because of the built-up air pressure inside the airtight plastic tank that forces the water out of the tank in an explosive rush.

Avoid Clogs With Pressure-Assisted Flushing Power

Another great reason to invest in a pressure-assisted toilet for your home is that the enhanced flushing power reduces the need for second or third flushes to clear waste from the toilet bowl. Instead of relying on gravity and centrifugal force to push waste out of the toilet bowl, the built-up air pressure in the tank blasts water into the toilet bowl, ensuring that waste flushes effectively.

Additionally, the high-velocity flush of a pressure-assisted toilet tends to break up large pieces of waste, preventing clogs in the toilet and further down the drain line. This means that you won't need to worry as much about using a plunger, a drain snake, or harsh drain-cleaning chemicals that can do lasting damage to your plumbing system if they are not used according to the directions and flushed properly.

Reduce Cleaning Frequency and Condensation Problems

A key (and often overlooked) difference between gravity-flow toilets and pressure-assisted toilets is that pressure-assisted toilets require less cleaning. The reason for this is that the strong force of the flush removes debris from the inside of the toilet bowl. In addition, the water level in the toilet bowl of a pressure-assisted toilet is higher than the water level in a gravity-flow toilet. The increased water level helps to keep the sides of the bowl clean during use.

You will even find that condensation is less of an issue because the water is stored inside an airtight plastic tank instead of a porcelain tank. Porcelain is susceptible to temperature changes and will frequently sweat during the warmer months of the year. With a pressure-assisted toilet, the plastic tank holds the water so it doesn't touch the sides of the porcelain and condensation cannot form on the outside of the toilet tank. Note that condensation issues can still occur on the toilet bowl.

Key Shortcomings of Pressure-Assisted Toilets

Despite the many positive reasons to have a pressure-assisted toilet installed, there are some drawbacks that could have you questioning whether the pros outweigh the cons. The increased flushing power that is so effective at clearing waste, preventing clogs, and even reducing cleaning frequency comes at quite a literal cost. While gravity-flow toilets can be purchased for around $100 to $300, pressure-assisted toilets typically cost around $500 to $700.

You should also take into consideration the noise produced by flushing a pressure-assisted toilet. As mentioned, the flush is explosive, which means that the sound of the flush is much louder than that of a standard gravity-flow toilet. For some people, this is enough to put an end to their interest in pressure-assisted toilets. Others are more concerned about maintenance and repairs because assisted flush toilets are not as common as standard gravity-flow toilets, so it's more difficult to find parts.

Whether you feel like the benefits outweigh the shortcomings or that pressure-assisted toilets aren't for you, it's hard to deny why they are a popular choice for anyone looking to save on water bills or reduce the frequency of clogs at home.