Gravity vs Pressure-Assist Toilets: A Detailed Comparison

Written by

Paulk Webb


Freddie J. Hagopian

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gravity vs pressure assist toilets

You may be after a toilet’s size, height, and aesthetics. It’s just understandable as comfort and bathroom décor matter. However, you must not forget about functionality. When it comes to toilets, you can discover them through its flushing system. Therefore, it takes you to weigh things on gravity vs pressure-assist toilets.

A gravity-fed toilet allows water to enter the bowl to flush down the waste after lifting the flushing valve through a handle lever. On the other hand, a pressure-assist toilet works with air aside from water. The water that comes out of the rim, together with the waste, is sucked by the pressurized air. More specifications will be shown as you continue to read.

Knowing Each Toilet


Before comparing certain points on pressure-assist toilets vs gravity fed toilets, let’s take a look at each toilet.

1. Pressure assist toilet

How does a pressure-assist toilet work? This toilet works with pressurized water to send the water and waste to the sewer. Just like everything else, it has pros and cons.

  • A pressure-assist toilet is stronger than a traditional toilet that functions through gravitational force. It efficiently flushes down the waste with less water.
  • It doesn’t require much cleaning because the water bulk is in the bowl to remain clean for a reasonable period.
  • The tank system of this toilet minimizes sweating and condensation. Hence, it doesn’t increase the humidity in the bathroom.
  • Flushing this toilet can be noisy and it’s something that you can’t experience from a toilet that functions with gravity.
  • Some parts for replacement are hard to find. You have to place a special order or visit a plumbing supply house in person.

2. Gravity-fed toilet

The flushing system of this type of toilet begins with a chain attached to the flush lever. In addition, the end of this chain is connected to the flapper valve. This valve uncovers the hole in the tank to release the water from the tank.

  • Since this toilet has a simple design, necessary repairs at some point don’t need a professional. You can do it yourself as there are fewer parts that you need to move. Hence, you don’t have to spend a lot on repairs.
  • The flush handle and the chain may cause an issue on this toilet. Some users just found that it doesn’t flush even though the handle is down. It happens when the chain connected to the flapper has loosened at one end or come undone. The chain can be too long so flushing doesn’t go through. In this case, you have to tighten the chain to get rid of slackness.

Evaluation of the Functions of Gravity Toilet and Pressure Assist Toilet


1. Water usage

The gravity toilet consumes more water than the pressure assist. Every flush requires 6 gallons or 4 gallons if it’s the assisted type. Aside from consumption, leakage can also increase water usage. It happens in the gravity toilet when the filler pipe continuously spills water into the tank.

This is not a usual issue on pressure-assist toilets because of the watertight cylindrical part in the tank. Furthermore, there will be no water sitting in the bowl. So, you don’t have to worry about bacteria forming on your toilet. You have to be conscious about hygiene to avoid any diseases.

2. Efficiency and hygiene

Due to the ability of pressure to get rid of every bit of waste, it’s deemed hygienic. As long as there’s no problem with its system, it can serve high traffic daily. However, it’s not the case with the gravity-fed type. A high number of users can create a mess so you have to clean often.

There will be some bits of the waste left in the bowl. You can use effective cleaners like Kaboom and Clorox. With pressure-assist toilets, it’s a rare case that some waste is left behind after flushing. In many tests, a pressure-assist toilet can discard balls and books.

3. Maintenance and repair

A gravity toilet can have leaks and breakage due to the temperature fluctuations like the cold-hot-cold-hot pattern. So, you can expect the need to go to a hardware store to buy some parts. But don’t worry as it’s easy peasy. Even though you have to do some repairs, this toilet will surely last for a long time.

The pressure assist toilets are a new creation with a complex design like the pressure cavity inside their tanks. Parts for replacement sometimes require looking further, but it’s easy to look for them online nowadays. Apart from more time and effort looking for a replacement, some pressure-assisted toilet problems can only be fixed by a specialist. It means that you have to spend a lot.

When you have issues with a gravity toilet, you can do the necessary repair by yourself. You have to realize that the pressure applied in the operation of a toilet can attack the nozzles and joints of the pipe. Thus, you must have the right pipes so leakages won’t occur often.

4. Noise

Despite being recently developed, the noise coming from a pressure-assist toilet still has no resolution. As mentioned, the air is involved in its operation. The air displacement takes place in the pressure cylinder. Then, the air runs through the system when flushing, and an airplane-like noise also comes out.

It can be a bother in the middle of the night when it’s quiet and you can wake someone out. This is not a problem with traditional toilets that operate quietly.

5. Water supply

Since gravity is what makes traditional toilets work, there’s no need to integrate pressure. When pressure is applied to a toilet, it’s a must to have a strong, consistent water supply. This concern is not necessary if you have a traditional toilet. It is when you have the new models. With this demand, you can’t take the pressure-assist work when you live on top of the hill.

Furthermore, the water supply must sit well on 25 lb. per square inch so air placement can create pressure in a toilet tank. You can check if you can meet this criterion by a pressure gauge. Those who are not familiar with this can hire a professional to do the process.

6. The matter or pressure

Generally, pressure-assist is more expensive than the gravity type. It’s made of ceramic and it has an intricate pressure cylinder inside its tank. In some houses, there will be a need to replace the pipes with stronger ones that can resist pressure. So, it’s an additional expense but you have to do it for the sake of safety.

7. Matter of pressure

Are pressure-assist toilets dangerous? Based on the Consumer Product Safety Commission data, 300 toilets ruptured because of inappropriate pipes. 14 serious injuries were reported because of this. Thus, 2.3 million pressure-assist toilets were examined for possible danger.

The gravity-fed is also made of ceramic, but it has only a few components due to its simple design. Therefore, the usual pipes can support its operation without demanding for tougher pipes.

What Is a Vacuum Toilet?


Is a vacuum assist toilet similar to a pressure assist toilet? No, it’s not as it has suction when flushing. This suction works with the vacuum tank as it sucks the waste and water from the bowl. It’s the recent innovation in the flushing system. The strength of its flush is reliable and it doesn’t sweat. Although it can be costly, repairs are done easily.

Flush it Down – The Conclusion!

Comparing gravity vs pressure-assist toilets is by weighing the pros and cons as well as the advantages and disadvantages. It clarifies which one is right for you. Price, water supply and consumption, maintenance and repair, efficiency and hygiene, and operation help you decide. Once you understand how each toilet works well, you can match one of them to your needs, preference, and house setting.

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