Pressure-Assisted Toilets: Everything You Need to Know

Last Updated on August 25, 2023 by toilethaven

What is a Pressure-Assisted Toilet?

A pressure-assisted toilet is a type of toilet with a secondary tank inside the main toilet tank called a pressure vessel. The pressure vessel holds compressed air, which mixes with inflowing water from the supply line to create a decisive flushing action.

So, how is a pressure-assisted toilet different from a gravity flush toilet? Pressure-assisted toilets are a minor modification of the basic gravity flush toilets. As a matter of fact, you wouldn’t tell a pressure-assisted toilet and a gravity flush toilet apart by just looking at them. You would need to remove the tank lid of each.

A gravity flush toilet depends on gravity 100% to move the water from the tank to the bowl so as to flush the toilet. For that to happen, water has to be moved from the tank to the bowl within the shortest time possible.

The action of dumping a large amount of water in the bowl suddenly is what creates the siphoning effect at the toilet trap. This is why modern toilets have a wider flush valve to move the water from the tank to the bowl fast while at the same time utilizing less water.

Pressure-assisted toilets are better at flushing solid waste compared to gravity-flush toilets. The pressurized water helps to create a stronger siphon. Pushing waste out of the bowl powerfully means you will never have to flush twice, and the toilet will hardly clog.

On average, pressure-assisted toilets will cost more than gravity flush toilets. A decent pressure-assisted toilet will cost upwards of $500. That said, gravity flush toilets cost way more than pressure-assist toilets, depending on their features.

Pressure-assisted toilets can and have exploded. This happens at or near the vessel weld seam. When that happens, the water stored in the vessel under pressure is released suddenly, lifting off the lid and shuttering the tank.

Pressure-assisted toilets make more sense in areas where a gravity-flush toilet would not suffice. If you have struggled with toilet clogs no matter what gravity-flush toilet you install, a pressure-assisted toilet might be what you have always needed.

How a Pressure-Assist Toilet Works

  • The pressure valve draws air into the pressure vessel.
  • Inflowing water from the supply line is forced into the pressure vessel.
  • When you flush the toilet, the compressed air forcefully pushes the water into the bowl.
  • A stronger siphon/suction action is created at the toilet trap, which flushes the toilet.
  • The pressure vessel draws more air and water for the next flush cycle.

When low-flow toilets were introduced, toilet manufacturers had to get innovative in order to produce toilets that flushed strongly after only one flush and did not clog frequently. It was possible to do that with a 3.5 gallons per flush toilet but not 1.6 gallons and below.

One way of doing that was to make toilets with large flush valves (3/ 4 inch) and extra-large trapways. Another way was making pressure-assisted toilets.

The pressure-assist toilet we have looked at above is the most common one, but there are others that differ slightly from these ones. Let us have a look at how the others also work.

1. Tankless Toilets

Dyconn Faucet

As their name suggests, tankless toilets are toilets without a toilet tank. So, how does a toilet without a toilet tank flush? To answer that question, you have first to understand the importance of a toilet tank.

The toilet tank acts as a reservoir to supply the bowl with the necessary water required to flush the toilet every time. They are installed on top of the bowl to give the water a bit of force as it moves down.

What if there was a way of supplying the bowl with the required water by bypassing the tank? This is where the tankless toilets come in.

They have a small pump that supplies the bowl with water under high pressure, sufficient to flush down its contents. This negates the need for a toilet tank. Tanks are installed in toilets because the water in most houses does not have sufficient pressure to flush the toilet.

Tankless toilets have been used in public bathrooms for years but are slowly making their way into private bathrooms. These toilets are both sleek and stylish but a little pricey.

In case you would like to learn more about tankless toilets, check out this post.

2. Rear Discharge Toilets

Rear discharge toilets are toilets that discharge waste from their back and through the bathroom wall, unlike floor outlet toilets. They are preferred as the best option for a bathroom far from the sewer line and one without a floor drainage system.

The problem with rear discharge toilets is that a gravity flush system might not suffice because the toilet trap is not as long as in ordinary toilets. The siphoning effect is, therefore, weaker and a weaker flush.

For this reason, rear discharge toilets are mostly also pressure-assisted toilets. To see a few of the best rear discharge toilets, check out this post.

3. Upflush Toilets


Upflush toilets, also known as macerating toilets, are installed below grade or far from the sewer lines. They pump waste both vertically and horizontally, making them a favorite choice for basement bathrooms. They also give you a chance to add an extra bathroom fixture.

Upflush toilets have a unit at the back called a macerator. The macerator contains blades that rotate at a high speed, breaking down the waste into a slurry that is then pumped out. To have a look at the best upflush toilet, I wrote this post that might be helpful to you.

With the three examples above, it is important to take your time to know what kind of pressure-assisted toilet would be most beneficial to you.

Pros and Cons of Pressure-Assisted Toilets

Just like any other product, pressure-assisted toilets have their advantages and disadvantages. While the advantages outweigh the disadvantages, it is still good to be aware of what to expect.

The Pros

The following are the advantages of installing a pressure-assisted toilet:

1. Powerful Flush

I might be wrong, but the number one most care about while shopping for a new toilet is its flushing power. Everyone hates flushing twice. And that is the problem that pressure-assisted solves.

2. They clog less

Once you buy a pressure-assisted toilet, a toilet plunger will be one of those things you will rarely need. These toilets are better at flushing solids than any other toilet. The pressurized water forces all the waste through the trap and down the drainpipe every single time.

Pressure-assisted toilets are the most recommended for people who habitually clog the toilet due to medical reasons or any other reason.

4. Water-efficient

You would expect pressure-assisted toilets to use a ton of water, but they are surprisingly very efficient. Most of these toilets use only 1.28/1.6 gallons per flush.

As a result, some of these toilets are certified by WaterSense, a program run by the Environmental Protection Agency to encourage less water usage. They can be sold in every corner of the United States.


5. Stops Toilet Tank Sweating

Toilet tank condensation, which is also called toilet sweating, is a phenomenon experienced especially in humid areas. It is caused by a temperature differential between the inside of the tank and the surrounding environment.

As the tank fills with cold water, condensation occurs outside the tank, and water starts dripping on the bathroom floor. The double-tank system of the pressure-assisted toilets means that the toilet tank is insulated and, therefore, no more toilet sweating.

6. Easy to Clean

Due to the pressure delivered by this system, the water level in the toilet bowl is higher than in ordinary toilets. Waste there does not stick on the bowl’s surface, making the bowl look clean at all times.

Pressure-Assist Toilets Cons


These are some of the disadvantages of installing a pressure-assisted toilet:

1. They are loud

Have you ever used a toilet on a plane? If you have, you then know how loud they are. But of course, the flight attendant must have uttered the words “This is a pressurized cabin” prior to taking off.

That is exactly how loud pressure-assisted toilets are. The water leaves the pressure vessel forcefully, resulting in an even more forceful flushing and loud flushing.

The noise will concern you for the first few days, but when you get used to it, you will not even notice it.

2. Replacement parts are harder to get.

With ordinary flush toilets, you are guaranteed to get a fill valve or flapper in your nearest home improvement store. That, however, is not the case with pressure-assisted toilet parts.

Few people own pressure-assisted toilets, and most home improvement stores don’t see the economic sense of storing the replacement parts. This is because they don’t sell fast, and that is deadstock to them.

You might need to order online and wait for a few shipping days.


3. They are expensive

Pressure-assisted toilets are more expensive than ordinary gravity-flush toilets. This is because most toilet manufacturers have to outsource the pressure vessel from a third party like Sloan.

Having said that, it is also correct to say that pressure-assisted toilets are not the most expensive toilets. Many gravity-flush toilets are more expensive than pressure-assist toilets.

Pressure-Assisted Toilets Reviews

The following is a review of the best pressure-assisted toilets in the market. If you are looking to buy one, then you wouldn’t go wrong with any of these.

1. Kohler K-3493-0 Highline

On Sale
Kohler K-3493-0 Highline Classic Pressure Lite...
  • Two piece toilet
  • Elongated bowl offers added room and comfort
  • Pressure Assist flushing system

 The Kohler K-3493-0 Highline Classic Pressure Lite is a two-piece, elongated, comfortable height pressure-assisted toilet. You can find it in almonds, biscuits, black and white.

This is one of the best pressure-assisted toilets on the market. It uses the Sloan Flushmate tank system, so you can be sure that it is quality. By the way, Sloan is the industry leader in the manufacture of pressure-assist toilet systems.

This toilet has an elongated bowl that is more comfortable to sit on than a round one. It is also a comfortable height toilet. The distance from the bottom to the top of the bowl is 17.125 inches, which is easy to sit and stand from.

Its dimensions are as follows:

  • Depth: 30.56 inches.
  • Width: 21.25 inches.
  • Height: 31.25 inches.
  • Rough-in: 12 inches.

Unfortunately, this toilet uses 1.6 gallons per flush and cannot be sold in some States like California and Texas. It also does not come with a toilet seat; hence, you will need to buy one separately.

2. American Standard 2467.016.020 Cadet

American Standard 2467016.020 Cadet Right Height...
  • Combination bowl and tank, less seat
  • Pressure-assisted siphon jet flush action
  • Low consumption (1.6 gpf/6.0 Lpf)

The American Standard 2467.016.020 Cadet is a single-flush, two-piece elongated pressure-assisted toilet. It is available in white, bone, and linen.

Many people cannot buy a toilet unless it is American Standard. If you are one of those people and happen to be looking for a pressure-assisted toilet, then look no more.

The Cadet flushes powerfully, and you would never need to use your plunger again. It has a 2.125-inch fully glazed trapway to improve its flushing process further. Like any other American Standard toilet, its surface is coated with its EverClean antimicrobial additive, preventing mold, mildew, and bacteria from adhering to it.

Some of its dimensions are:

  • Depth: 30.25 inches.
  • Width: 20.5 inches.
  • Height: 29.25 inches.
  • Rough: 12 inches.
  • Bowl height: 16.5 inches.

It consumes 1.6 gallons of water per flush and does not come with a toilet seat either. You will, however, receive color-matched toilet tank bolt caps.

3. Saniflo SaniAccess 3

SANIFLO Saniaccess 3 + Toilet Bowl Elongated +...
  • THE ULTIMATE BUNDLE: Our bundles have our customers in mind when it comes to getting all they will need for their new upgrade or bathroom. With the Saniaccess 3, toilet bowl and toilet tank bundle,...
  • DUAL PURPOSE: The Saniaccess 3 will also discharge gray water from any sink, bath/shower or urinal. The wastewater will drain into the system with built-in check valves on either side of the housing.
  • MAKES MAINTENANCE A BREEZE: There are 2 easy access service panels located on top of the pump. On one, you can easily access the electrical components and level sensor. On the other, you can access...

Saniflo is the best manufacturer of upflush toilets, and Saniflo SaniAccess 3 is the best upflush toilet, in my opinion. If you are looking to install a toilet below grade or further away from the sewer line, then this is the toilet to buy.

It is a single-flush, two-piece elongated rear discharge toilet. It, therefore, does not require you to dig up your bathroom floor to install a drainage system. This toilet can be installed up to 15 feet below a sewer line and 150 feet away from a soil stack.

Apart from the toilet, you can also install a sink and a bathtub/shower. The macerator unit has two other inlets (apart from the toilet inlet) to accommodate other bathroom fixtures. The waste is pumped out as soon as it enters the unit.

You can choose to install the macerator directly behind the toilet or behind the toilet wall. If you choose to have it on the wall behind the toilet, be sure to buy the connector pipe.

This toilet is a little pricey but is very well-made and works as advertised. Unlike other pressure-assisted toilets, it needs a constant supply of electrical power. Its consumption is only 1.28 gallons per flush.

4. American Standard 2315.228.020 Baby Devoro

American Standard 2315228.020 Baby Devoro FloWise...
  • BEST-IN-CLASS: This low height American Standard Baby Devoro residential toilet is perfect for any project where a small person or child is the intended user; this toilet is also perfect for education...
  • PERFORMANCE: The American Standard Baby Devoro toilet features a MaP score of 500 grams and a speed connect toilet tank & toilet bowl coupling system
  • FLAWLESS DESIGN: This American Standard toilet is designed with a fully glazed 2-1/8 in. trapway and the inclusion of a round siphon action jetted toilet bowl. 10 x 9 in. (254 x 229 mm) water surface...

American Standard 2315.228.020 Baby Devoro Flowise is another great pressure-assisted toilet from American Standard. It is a single-flush, two-piece round toilet available only in white.

This toilet is best suited for people who want to replace their old 10-inch rough-in toilets with a modern flushing one. It is also good to realize that this toilet has a round bowl.

Round toilet bowls are the best option for people with smaller bathrooms because they are smaller in depth than elongated ones by 2 inches. They are mostly found in old houses.

Another thing to consider is that this toilet is pretty short. The bowl height without a seat is only 10.25 inches. It is, therefore, a very good toilet if you are looking to start potty-training your young ones.

The Baby Devoro is EPA WaterSense certified. This is because it only uses 1.28 gallons of water per flush. You will, however, need to buy a seat separately.

Its dimensions are:

  • Depth: 25 inches.
  • Width: 17.25 inches.
  • Height: 24.5 inches.


1. Does Toto make pressure-assisted toilets?

Toto does not make pressure-assisted toilets. They believe their gravity toilets are designed to comfortably and quietly flush any waste, negating the need for a loud pressure-assisted system.

If you would like a powerful gravity-flushing toilet, I have reviewed some of the best ones in this post. You can get the best Toto toilets there also.

2. Can Flushmate be installed in any toilet?

No. Flushmate only works with toilets, which were initially designed as pressure-assists. The toilet tanks and bowls of pressure-assisted toilets are designed differently from those of gravity flush toilets, and the system can not be retrofitted.