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How Different Types of Tankless Toilets Work

How Do Tankless Toilets Work
Written by Elizabeth Fincher

How Do Tankless Toilets Work? – Different Parts of a Tankless Toilet

Special valve

Instead of using gravity to flush away the water in the tanks like regular toilets with tanks, tank less toilets connect directly to the pipes using an electric pump to power the flush. Usually, it is located in the bowl. The valve allows only a certain amount of water to enter the bowl when flushed and ensures that the toilet doesn’t overflow. The draining for tank less toilets however works similarly to a traditional toilet.


Since tank less toilets do not use tanks to flush away the remnants of the toilet bowl, it uses a Flushometer to serve that purpose. Flushomter is the fixture where the water enters from the supply line at great pressure to force the waste through the drainage system. This fixture needs about 1.6 gpf  of water pressure to function correctly. Some manufacturers even shoot for 0.8 gpf.

Pros & Cons of Using Tank Less Toilets


  • Powerful flush
  • Depends on electricity
  • Saves space & water
  • Difficult to repair
  • Environment friendly


  • Expensive than traditional toilets
  • Sleek design
  • Noisy flush
  • Fairly easy to clean
  • Difficult to install

How Different Types of Tankless Toilets Work

Pros & Cons of Using Tank Less Toilets

Tankless toilets in commercial buildings

The most widely used tank less toilets in public are the urinals. The majority of urinals operate with the help of a valve that is metered with a diaphragm or a piston. Impressively, the valve is designed in such a way that it automatically shuts after a flush cycle has been completed. No other computer or technology is used to regulate this activity.

For most models of the traditional flush-valve tank less toilets, there can be a degree of user control. Building owners can make small adjustments to flush volumes. But in many countries including the United States, the owners must act in accordance with the national standards for using water. Some features such as ‘hands-free flush technologies’ and ‘water –conservation devices’ can enhance the performance of these toilets.

In commercial settings, the functionality of all tank less toilet models work almost identically. Upon flushing, a valve opens a supply line to let a certain amount of water gush into the bowl. According the U.S. Department of Energy, the current standard of water usage for urinals is 1 gallon or 3.80 liters

Tankless toilets in urban apartments

Residential tank less toilets that rely on the flush valve technology have minimal difference than those in public restrooms. Due to their high water pressure requirement, unfortunately they are less common in homes. New York is an exception in this case.

In big cities like the aforementioned, tank less toilets are popular in residential settings for their space saving feature.

The more modern versions of these toilets are sleeker and have features like seat heating and self- cleaning systems

Flush assisted tankless toilets

These toilets come in various stylish designs and modern mechanisms. Some work with computer controlled valves to release water in stages and others run solely on electricity.

How Do Tankless Toilets Work & Which One Should You Get?

In order to decide whether you should get a tank less toilet depends on a bunch of factors:

  • Installing one of these toilets could damage the pipes of your bathroom and cost you extra
  • Pipes must be bigger and stronger to withstand the high powered flushing. A lot of pressure is exerted on the pipes during the process. So these toilets might not be suitable for old buildings.
  • It must be made sure that an electric power supply is present at the spot.
  • In areas prone to frequent power outages, tank less toilets will be useless when you need them the most.
  • The installation cost of these toilets are immensely high. The minimum cost is $1000 and can reach upto $5000!

On the other hand,

  • They require very little maintenance, and make your bathroom spacious.
  • There’s no need  to worry about leaks
  • If your building is low traffic and has a generator backup, you could go for it.
  • They’re candy for the eye and will serve you well in a small bathroom.


1. Can you flush a toilet without a tank?

Ans. Tankless toilets let you flush away the remnants as they are connected directly to the water supply and have a flushometer. It exerts high pressure into the toilet bowl while making sure that only the adequate amount of water is released while flushing away.

2. How much water pressure is needed for a tankless toilet?

Ans. Flushometers in the tank less toilets require a pressure of 20 PSI to refill faster and create cleaner flushings repeatedly compared to their counterparts.

About the author

Elizabeth Fincher

Elizabeth started her career as an interior design artist at a multinational interior design farm. She completed her masters degree from the University of North Texas back in 2010. She was also a Spelling Bee runner-up when she was 14. She took interest in bathroom interior designing after joining her first job. Later she started her own firm as an independent artist. She’s been one of the founding members of Toiletsguide. She examines the design and ergonomics of the units we review and directs the interior decoration team of our in-house research facility. Elizabeth plays piano masterfully and always finds time to entertain us in between our busy schedules.

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