Water Efficient Toilets: Save up to 90% Water Used


By using water-efficient toilets, we can save up to 90% of water what we use now. The water saving in the toilet can be achieved by vacuum, pressurised flush, dual flush, Siphonic trap or cyclone flush.

One or more mechanism is used in the toilets to achieve high efficient flushing with low water usage.

Don’t think the water efficient toilets will have difficulty to flush the waste from the bowl. In fact, the flushing achieved by these toilets is much adequate compared to the toilets what we used 10 to 15 years before.

These toilets work on different principles, based on this the principle the necessary water for flushing varies.

By using this toilet, we can save a lot of water for the future. The water is not an unlimited resource. Already the ground water level is going down and some areas the groundwater is no more. And the investment on this kind of toilets can be quickly recovered from the water bill saving.

There are some countries/states have rules that you must use equal to or less than1.6Gallon/Flush or  6 litre/flush. Some governments also provide Fund for replacing the old toilet with new water saving toilet.

We are talking about minimum 50% to 90% water saving.

Some of the water efficient toilets are more suitable for commercial malls and more populated areas. Imagine how much water is used in a public toilet in a crowded place. Using the best toilet in these areas will allow more water-saving than any other areas.

Nowadays toilet manufacturing companies also coming up with the new design and new technologies to use less water to flush the waste effectively.

In this article we are going to see the different type of water saving toilets and how this toilet works better than the traditional toilets:

Vacuum Water Saving Toilets:

This is the best in this category. You can see this type of toilet in planes. And nowadays this kind of toilets are installed in commercial malls, Public toilets and etc.

The required water for a single flush is less than 500 ML / 0.132 Gallons. Compared to 1.6 Gallon or 6 litter flush toilets, this toilets use only 8.3% of water consumption compared to the traditional flush toilet. So that means this toilet can save 90% of the water every time someone flushes this toilet.

This technology is introduced in plane to reduce the water storage for toilet and the waste storage. This helps the plan to fly with low weight and use low fuel and reduces the cost of flying. I believe we are also at the critical time to save every drop of water.

See the video top understand how this toilet works.

A vacuum chamber is connected to the toilet drain. Every time when we flush the water a small quality of water rinses the toilet blow, and after a few seconds the vacuum machine sucks the waste through the trap way and empties the toilet.

Then a small amount of water is pushed to rinse the blow again leaving the toilet to look like same as the initial condition, and it is ready for next usage. From the video, you can see how much less water is used to clean and flush the toilet.

This toilet installation in the home environment is difficult because of the machinery used and the noise created during the flushing.

But this toilet can be adopted in commercial areas. When used in commercial areas the water saving by this toilets are enormous.

The disadvantage of vacuum toilet:

Installation cost is high because of the required equipment for the vacuum suction.

Noise during flushing of the waste(suction of the waste during vacuum process).

The advantage of Vacuum Toilet:

Highly efficient compared to other toilets can save upto 90% of water.

Siphonic water efficient toilet:

The siphonic toilet is the first toilet design which started the concept of water saving in the toilet to the world. The toilet uses a simple suction principle to flush the waste efficiently.

This toilet almost looks same like standard toilets if it is a concealed toilet but siphon principle achieves the flushing. Below is the image show the difference between the Normal toilet and the siphonic toilet.

Siphonic Water Saving toilets

As you can see, the main difference is the trap way of both toilets. The siphonic toilet trap way is almost twice as long as the regular toilet.

Siphonic toilets are available in different flushing capacities. You can get like 4Liter/Flush and also 3 Litter/flush. This model is available in the regular market; there won’t be any difficulties to get these toilets.

You can get one piece and two piece models in siphonic flushing.


Cost is comparatively low than any other toilet listed in this article.

No noise compared to the vacuum or pressurised flushing.

No Water Tank Toilet:

This is new model water saving toilet in the market. As the name suggests this toilet looks like no tank attached to it, but this has attached the tank to it which very small.

This toilet flush is 2 Liter/Flush (0.528 GPF).

No tank water save toilets

I got to know this product through LinkedIn. This product is patterned for the new flushing system. This toilet uses only 2liters /0.528 Gallons per flush. That is an incredible improvement for flushing.

The Product information says that no need for electricity or dry battery only needs direct tap water connection.

Spiral Flush or Tornado flush:

Both names suggest same flushing principle. The water is flush to the bowl in such a way that it creates a circular motion cleaning in the bowl. This design of toilet bowl usually is round to facilitate the water to flow in circular motion.

This centrifugal force helps for better flushing. And also this kind of toilets clean the toilet bowl 360 degrees, which is not always achieved in other toilets. This makes this toilet cleaner in the bowl area every time we flush it.

These toilets are generally including the siphonic principle also to the design which enables the flushing better.

Many companies produce this kind of toilet. The Toto cyclone is a famous model which works on this technology. Duravit tornado also works on the same principle.

Pressure Assist Toilet:

The flush will be happening by the pressure assisted water. The pump inside the tank will pressurize the water. Because of the force of the water, the flush is much effective than the standard cistern flushing.

This toilet is not recommended because there is a possibility of an accident because of the pressurized vessel inside the tank.

Even there are some incidents where the tank is exploded because of the heavy pressure and some companies recalled the products and made it more secure and returned to customers.

Direct water Connection To tank

I would suggest staying away from this model because the risk is not worth it. There are much better models which flush better without any issue. Then why need to go for this model.

Another model of this type is pressurized water connected to the toilet. Some big apartment will have a significant water tank on top of the flats. Because of this water flows in high pressure to the pipe so the pipe is directly connected to the water closet.

A pressure lever is used to flush the toilet when it is necessary.  When the pressure lever is pressed, high-pressure water is forced into the toilet to flush the waste out.

Dual flush toilet:

This toilet will be very helpful to save water in residential bathrooms. The flushing mechanism will have two buttons. They are,

1)    Full Flush.

The full flush is for removing the human waste. It flushes 1.6 Gallons per flush.

2)    Half Flush.

This button is used when to flush out the urine only. When pressed this button only one-third of full flush water is flushed.

Imagine a house with children, how many times they flush when they urinate on the toilet. This type can save a lot of water in residential bathrooms.

Dual Flush button tank water toilet

In the market, this flush is available with the siphonic water saving model.

Recycled Water toilet:

There is no particular mechanism for this toilet. The toilet uses the used water for flushing.

Usually, a washbasin is attached to the top of the toilet just like a tank lid. So whenever anyone washes the hand using the washbasin the tank is filled with the water used and it used during the flushing.

See the image below to understand the concept of this toilet.

Some instance the washbasin will be in separate place, and it will be connected to the toilet to use the used water as a flushing purpose.

Zero Water Toilets:

In the market, there is zero water consuming toilets available. There are some advantages and disadvantages of this toilet. For my view, these toilets are not entirely solving the problem.

They do remove the problem of water consumption, but they create a new issue like smell ventilation, Toilet bowl cleaning and toilet paper removal.
Now we see some of the zero Water Toilets.

1)    Composting toilet:

2)    Water less toilets.

3)    Pee Poo

Composting Toilet:

In Composting toilet the bowl is directly above the collecting bucket. When someone uses it, then they need to press a lever to open the small partition in between the bowl and the collecting bucket.

Once they finish it they need to add some biomaterial to it and close the collecting chamber. Using the mixer

The biomaterial and waste are mixed and bio-integrated to use it as a fertilizer for the plants.

Compared to other waterless toilets, I see the reuse of the waste to the plants is the only advantage it has. But they are many practical difficulties like how the bowl can be cleaned and how odour can be reduced. How long a collector can be used if there are 4 or more people is using this toilet.

Waterless Toilets:

There are various proposed ideas on the water less toilets.

One idea is proposed to burn the human waste to burn into ashes. Another idea is to deposit all waste to disintegrate using bio or artificial materials.

There are practical difficulties in these ideas and need to be perfected for day-to-day usage. Until we need to use the minimum water usage toilets so save water and keep the bathrooms clean.


These are simple cover with you can wrap it around the seat of a toilet and use it. Once finished you can knot the bags and throw under the soil.

The bag will disintegrate in the soil, after 4 weeks it can be used as a fertilizer.

For me, this idea is like we are going back to Stone Age.

Smart Toilet:

The intelligent toilet will save water by sensing the water required for flushing and flush only the necessary amount of water.

There is a reason for me to add this toilet in the last place in this list. I believe the toilet need to simple and this toilet uses electricity, and their many countries still don’t have 24 hours electricity supply to their residence. And these toilets use power and it is also a resource which we need to take into account.

Companies producing Water Saving Toilet:

In recent times major toilet manufacturing companies coming up with ideas to reduce the water usage per flush.

In last ten years, the design and mechanisms almost reduced the water consumption per flush to less than 50%. It is because of the continuous research and development on the flushing mechanism and the flushing principles.

Some of the MNC like Kohler, Roca, Toto all are created with a special focus on the water saving in bathrooms. Water saving is not only for toilets but it also for urinals, other kitchen and bathroom items. Equal to MNC there are many Chines, and Japanese toilets companies are coming with a design to save more water.

10 Water Saving toilets infographic


I have included all water saving toilet in this article even though some have huge disadvantages, to make sure for you to understand the difficulties of the toilets.

As you can see the, all the Water-saving toilets are working on different principle or combination of multiple principles to reduce the water usage.

We hope in future to see there will be much better toilets to save water or use no water at all to enable saving natural resource. We will be updating this article as we find any new technology in water saving technic.

If we missed any other water saving toilet or if you have any doubt let us know by commenting below.


  1. Thank you very much for this informative Article. It would have been better if you had recommended a water efficient commode type for home.

  2. iam riyaz physiotherapist, specialist in seating & mobility solution, assistive technologist, working for disabled population more than 10 years across india & developing countries. right now i’m working on the One idea is proposed to burn the human waste to burn into ashes. i would like hear from you more on this . if can share pro’s * con’s of this waterless design.

  3. We have floor mounted we but flushing is very poor…not enough water in the bowl and not enough pressure for flushing. Can you pl suggest a good make of floor mounted wc?

  4. I was just searching for a toilet with less flush water requirements for our proposed quarters. Thanks for the informative article.


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