Pressure-Assisted Toilets: Everything You Need to Know

Last Updated on May 18, 2022 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 powerful flushing action.

So, how is a pressure-assisted toilet different from a gravity flush toilet? Pressure-assisted toilets are actually 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. In order for that to happen water has to be moved from the tank to the bowl within the shortest period of time possible.

The action of dumping a large amount of water in the bowl suddenly is what creates the siphon-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, meaning 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, there are gravity flush toilets which costs way more than pressure-assist toilets, depending on their features.

Pressure-assisted toilets can and have actually 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 makes more sense to install 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 in 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 in 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 which differ slightly from these ones. Let us have a look at how the others also work.

1. Tankless Toilets

Dyconn Faucet

Tankless toilets as their name suggests are toilets without a toilet tank. So how does a toilet without a toilet tank flush? To answer that question, you have to first 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 for years been used in public bathrooms but are slowly making their way into private bathrooms. These toilets are both sleek, stylish but a little pricey.

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

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 therefore 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 which are also known as macerating toilets are toilets which are installed below grade and/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 and extra bathroom fixture.

Upflush toilets have a unit at the back called a macerator. The macerator contains blades which 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 3 examples above, it is important to take your time to know what kind of pressure-assisted toilet would be most beneficial 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 by far, 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 more than any other toilet. The pressurized water forces all the waste through the trap and down the drainpipe every single time.

For people who habitually clog the toilet due to medical reasons or any other reason, pressure-assisted toilets are the most recommended ones to install.

4. Water-efficient

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

As a result some these toilets are certified by WaterSense, a program run by the Environmental Protection Agency to encourage less water usage. They can therefore 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 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 take off.

That is exactly how loud pressure-assisted toilets are. The water leaves the pressure vessel forcefully resulting into an even forceful flushing action and hence a loud flushing.

The noise will however 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.

Not many people own pressure-assisted toilet and most home improvement stores don’t see the economic sense of storing the replacement parts. These is because they don’t sell fast and to them that is dead stock.

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

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 part like Sloan.

Having said that, it is also correct to say that pressure-assisted toilets are not the most expensive toilets. There are many gravity flush toilets that 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 any of these.

1. Kohler K-3493-0 Highline



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

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

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



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

I know a lot people who 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 further improve its flushing process. Just like any other American Standard toilet, its surface is coated with their EverClean antimicrobial additive which prevents mold, mildew and bacteria from adhering on 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 too. You will however receive color-matched toilet tank bolt caps.

3. Saniflo SaniAccess 3


Saniflo is the best manufacturer of upflush toilets and Saniflo SaniAccess 3 is the best upflush toilets 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 a single flush two-piece elongated rear discharge toilet. It therefore does not require you to dig up you 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 2 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 it is very well made and works as advertised. Unlike other pressure-assisted toilets it needs constant supply of electrical power. Its consumption is only 1.28 gallons per flush.

4. American Standard 2315.228.020 Baby Devoro



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 better flushing one. It is also good to realize that this toilet comes with a round toilet bowl.

Round toilet bowl 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 kind of waste therefore 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 originally designed as pressure-assist. The toilet tanks and bowls of pressure-assisted toilets are designed different from those of gravity flush toilets and the system can therefore not be retrofitted.