How Does a Tankless Toilet Work?

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A tankless toilet isn’t exactly the cutting-edge technology, but many homes still don’t have one. 

More often than not, the reason is a hefty price tag that makes homeowners wonder if it’s worth the investment. So, how does a tankless toilet work, and what makes it more expensive than installing a traditional toilet? 

It’s a surprisingly broad topic, so buckle up as I am about to show you:

  • The basics of a tankless toilet
  • Differences between tankless toilets and traditional toilets
  • Water consumption differences
  • The pros and cons of tankless toilets

What Is a Tankless Toilet and How Does It Work?

A tankless toilet is a water-efficient commode that provides an alternative to standard flushing toilets. They’re ideal for any household looking to reduce their monthly water bill and looking to conserve natural resources — but we’ll get to that later.

A tankless toilet, also called a high-efficiency toilet (HET), obviously has no tank. It doesn’t store water in a tank for use when flushing, as, instead, the water is supplied directly by the public water supply line.

The main reason homeowners go for Saniflo tankless toilets is that they do not use water until necessary, which means no excess consumption or waste. A toilet without a tank achieves this by sending water through the line at a faster rate.

A large percentage of commercial buildings have adequate water pressure to operate a tankless toilet flush without requiring mechanical aid. 

What Is the Role of a Flushometer?

Many people use the terms “tankless toilet” and “flushometer” interchangeably. A flushometer is a valve that controls the flow of the water and determines the quantity when flushing. American Standard is the most widely used flushometer. 

We recognize two main types of flushometers:

  • The piston valve flushometer: It contains a molded piston that separates the two chambers — one with low and the other with high-level pressure.
  • The diaphragm valve flushometer: This one has a rubber diaphragm rather than the piston to separate the two chambers.

The majority of flushometers activate in one of four main ways — a button, a motion sensor, a lever, or a dual flush.

A flushometer works like this: after flushing, the water goes through the valves and closes the high-pressure chamber. At the same time, it opens a low-pressure valve to let the water flow directly into the bowl.

A great thing about tankless toilets, AKA flushometers, is that they rarely ever need more than one flush to remove the toilet waste — the water pressure is simply too high. The smaller size and lack of internal moving parts also contribute to their efficiency.

What Is a Tank Toilet and How Does It Work?

When we talk about modern toilets, we compare them with traditional tank-based models. You can choose between different toilet seats and bowls, but the most common dilemma is whether to pick traditional or tankless toilets.

As the name suggests, a tank-based toilet like Kohler contains a water-filled tank on the top of the structure.

A traditional tank toilet works like this: when someone pushes the flush handle, a chain pulls up on a flapper inside the tank. This causes the tank to fill with water, which eventually overflows and flushes waste down into the drainpipe. 

Toilet Water Consumption Explained

Water consumption is one of the main differences between traditional and tankless toilets. It all comes down to choosing between 1.28 GPF VS 1.6 GPF toilets, but there are even stronger models out there.

Water consumption is a critical issue, as the US Environmental Protection Agency claims that toilets account for nearly a third of an average home’s indoor water consumption.

The US is particularly strict in terms of toilet water consumption. Federal authorities set clear borders for all types of users:

  • Toilets in single-family homes or commercial buildings are not to use more than 1.6 gallons (6 liters) per flush
  • Urinals are now limited to no more than 1 gallon (3.8 liters) per flush

Other countries like Australia and Canada are trying to implement the same water conservation rules. However, we are still far from seeing a uniform effort on a global scale.

The key question is this: Is there a significant water consumption difference between traditional and tankless toilets?

Yes, there is.

Tank-Based Toilets and Water Consumption

Typical tank toilets are much heavier water consumers than the average tankless toilet. Older toilets, built before the 1980s, eat up to six gallons of water per flush. Newer versions consume half that amount (approximately 3.1 gallons).

Bear in mind that tank toilets sometimes even need a couple of flushes to remove whatever is in the toilet bowl, maximizing water consumption.

Tankless Toilets and Water Conservation

Tankless toilets are becoming increasingly popular because they work better for homes with little storage space. More importantly, tankless toilets help the environment by saving the amount of water used in each flush.

Today, a tankless toilet only spends up to 1.6 gallons per flush. And, many manufacturers are even going well below 1.6 gallons per flush — reaching as little as 0.8 or 0.9 gallons. It’s a new way for manufacturers to gain the advantage over their competitors, and it also suits eco-friendly policies. 

It’s a major improvement compared to the traditional tank toilets of the 20th century.

Additional Features of a Modern Tankless Toilet

Homeowners don’t just like tankless toilets for their environmentally friendly functioning — they also enjoy quite a few benefits and special functions that tank toilets do not provide. Tankless toilets are more advanced, so you can get a few extra features. These add to the overall convenience and turn your toilet into a multifunctional tool.  

Here’s what a tankless toilet, like Woodbridge, can do for you:

Air Purification

Some tankless toilets have special filters to clean the air inside the bathroom and keep it as fresh as possible. This feature is beyond the reach of older tank toilets.

Motion Detection

With a built-in motion detector, a modern tankless toilet can activate without any manual intervention from your side. The user only needs to sit down on the toilet seat and wait for it to do its job. Advanced models even offer voice activation for ease of use.

The Self-Cleaning Function

New tankless toilet models come with an automatic self-cleaning function to maintain the bowl at all times.

Toilet Seat Heating

Toilet seat heating is also known as eDOT (Electronic Dot Technology). It turns on automatically when someone sits on the toilet bowl and warms up the cold toilet seat.

Spray Massage

Some manufacturers offer toilets with an integrated spray massage. It resembles a bidet with a smooth massage function for extra hygiene and comfort.

Remote Control

I can’t help but mention tankless toilets that allow owners to control and operate remotely. All it takes is a smartphone app to change the settings, activate the flush mechanism, and adjust other features.

Advantages and Disadvantages of Tankless Toilets

No single bathroom element is perfect. However efficient and environmentally friendly, tankless toilets come with their own set of pros and cons.

The Pros of Having a Tankless Toilet

First, let’s take a look at the benefits of installing a toilet without a tank:

It Gives You More Space In the Bathroom

A tankless toilet saves a lot of space simply because it does not come with the extra element of a tank. It looks more streamlined, sleek, and modern than the traditional kind.

Water Preservation

The tankless toilet conserves water as it does not require the same amount as a traditional toilet. Water consumption goes down by at least two times, thus making a major improvement in water preservation.

Reduced Utility Bills

A tankless toilet also reduces utility bills. The logic is clear — homes using less water will pay less for water consumption.

It Improves Bathroom Hygiene

The very design of the tankless toilet reduces the number of germs and bacteria growing inside. A tankless toilet does not require a constant supply of water to flush out the waste, and means there is no chance for water stagnation.

Tankless Toilets Add to Bathroom Aesthetics

Minimalism is the name of the game in modern interior design, and a tankless toilet is often more visually appealing than the traditional option. It blends in better with today’s bathroom trends, which means it brings a fresh look to your bathrooms.

Special Features

We already discussed a broad scope of additional features you may find in a tankless toilet. Everything from seat heating and self-cleaning to remote controls and air purification is there to make your bathroom time more pleasant.

Increased Home Value

A tankless toilet is one of those little things that will impress potential buyers. In turn, it also boosts the resale value of your home.

The Cons of Installing Tankless Toilets

Tankless toilets have a few downsides as well. You need to take them into consideration before deciding which type to buy.

It’s Harder to Install Residential Tankless Toilets

Contrary to a tank toilet, tankless models require professional installation as the average homeowner does not have the required knowledge and tools to install one. 

And, since everything is behind the wall, the tankless toilet is also not easy for the layman to maintain.

The Installation Cost Can be High

Residential tankless toilets often cost more than traditional models, and the price tag reflects the extra labor needed to install them properly. The price also goes up significantly if you have to set up the electric pump for the flush system.

Tankless Toilets Make Noise

Unlike a tank toilet, the average tankless toilet is pretty loud when flushing. The noise generally comes from the electric pump that operates when you flush. 

The pump creates a high-pressure flow when you flush the toilet and makes noise in the process. The sound of the flush increases due to the stronger water flow. 

Some models come with a sound insulation feature, but even then it’s much noisier than the traditional kind. This can be a big issue in smaller homes — especially ones without adequate sound insulation.

Higher Water Pressure Damages Pipes

The noise isn’t the last issue with tankless toilets — the water pressure in the system is continuously high because water comes directly from the pipes. 

Average pipelines can only withstand higher pressure for so long, so it’s better to install wider and stronger pipes. These can withstand pressure for years without cracking.

If you go with the usual pipes, your supply lines will suffer greater pressure and probably even crack from time to time. This rarely happens with tank toilets.

You Need Water Filters 

Make sure that your tankless toilet comes with a built-in water filtration system. You should also get an external filter for improved performance and cleanliness, which is not an issue with a tank toilet.

Power Supply Stability

To work properly, tankless toilets need a stable power supply. You might find that your unit does not work well during the winter when electricity is very common to fluctuate. This is far from perfect because sometimes you may end up with a bowl full of poop that can’t go down the drains.  

You can face the same problem with the tankless toilet if you live in a neighborhood with frequent power supply pitfalls. 

In both of these cases, a tank toilet is probably a better option for your home.

The Bottom Line

Modern toilets don’t have a tank, but there’s nothing secret about the way they function.

A tankless toilet obtains water from a high-pressure supply line that is powerful enough to push waste through the drainage system. This means that, in case the water pressure is too low to support the tankless toilet, it is necessary to install the electric pump.

Tankless toilets have lots of advantages as they make it easy to conserve water and reduce utility bills. They provide more space in the bathroom and make a more aesthetically pleasing solution. 

A tankless toilet will also increase the value of your home and improve the overall experience.

This type of toilet is a good option to consider when remodeling a bathroom or building a new home. It will make your bathroom more spacious, beautiful, and comfortable.


Are tankless toilets reliable?

Yes, they are very reliable. Tankless toilets work well mainly because they feature fewer moving parts than traditional toilets — they require far less maintenance. 

You do not need to make repairs on them as often, if at all. The only downside is that the cost of fixing a malfunctioning tankless toilet is much greater.

Can tankless toilets overflow?

Tankless toilets can overflow if the water pressure drops below a certain point.

Tankless toilet tanks usually come with a manual override feature for emergency cases such as this one. In this case, the best option is to completely shut down the toilet and stop all functions until you flush it again manually.

Can I set up a tankless toilet in my home?

Installing a tankless toilet requires professional plumbing knowledge because it needs specialized venting and perhaps even re-routing of waste pipes. Good news, though: there are many DIY kits for tankless toilets. 

DIY instruction manuals will give you a step-by-step guide on how to set up a tankless toilet in your home. You’ll probably spend more time doing it than your plumber would, but you’ll feel the satisfaction of installing a new toilet on your own.

Of course, DIY kits also make the installation process more accessible for homeowners who want to save money.

Do tankless toilets take up less space?

Yes, tankless toilets take up less space than tank toilets. The reason is simple — they don’t contain the additional element (the tank), so they require less space in your bathroom.

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