What happens if you push both buttons on a dual flush toilet?

The dual flush toilet is gaining spectacular popularity around the world for its fantastic aesthetics and sensational working mechanism. You must have been using the dual flush toilet for a long time and using a separate flushing system for different types of waste. But have you ever thought about what would happen if you pushed both buttons simultaneously? Does it cause any irreparable harm to the toilet?

Pressing both buttons simultaneously can add more water to the toilet bowl, but we don’t recommend doing this. It will do nothing but waste water, as a full flush is enough to drain down solid human waste.

Consumption of water under different conditions (In GPF):

Type of FlushConsumption of water
Single Flush Toilet (HET)1.28 or 1.6 GPF
Single Flush Toilet (Conventional)3 to 5 GPF
Dual flush toilet (Small flush/ for liquid waste)Less than 1 GPF
Dual flush toilet (Larger flush/ for solid waste)1.28 to 1.6 GPF
Flushing both buttons at the same time2 to 2.5 GPF

What is a Dual Flush Toilet?

The dual-flushing system is not that popular around the world; people feel comfortable using the single-flush toilet instead. Now the question is, what actually a dual flush toilet is? The dual flush toilet is a special kind of toilet mechanism that uses two flushing options to remove different waste types. Literally, the liquid waste needs less water to be evacuated, and the heavy-duty solid waste needs more water to be evacuated through the Trapways. The main difference between the traditional single and the dual flushing toilet is that the latter consists of two different flush buttons, whereas the former has only one flush button.

How does the dual-flush toilet work?

The working mechanism of the dual flush toilet is a unique and authentic procedure you can ever find. The toilet brands have made this unique system to save some amount of water. Most of the cases, the liquid wastes need less water to sweep away the waste, but in the conventional system, we do not have that facility for flushing less water for light waste. Both the light and heavy-duty wastes use the same amount of water which is a total mess. To eradicate this toilet problem, the dual flush system has emerged.

Working mechanism: When you pee, flush the small button to sweep away the waste. And after defecating, press the larger button that may insert more water and more force into the toilet bowl, and it becomes easier to dump the dense waste. You can press both buttons simultaneously if you have more supporting waste, like tissue paper with feces. That might create more water pressure, and it becomes nonchalant to dump all the waste.

Some of the top-rated dual-flushing toilets are:

How much water bill can this system save?

The dual flushing system is appreciated all over the globe, especially in those regions where water is less available or scarce. The dual flushing system knows the difference between solid and liquid waste, which is why it allows a different amount of water for these two types of waste.

Okay, let us explore a simple calculation; suppose you are charged about $3 to $4 for spending every 1000 gallons of water. Now, this is the trick: the solid waste removal button uses almost 1.25 to 1.5 GPF of water, and the smaller button uses less than 1 GPF of water. That means that every single flush saves more than 0.5 gallons of water. If one flush saves more than 0.5 gallons of water, it can save more than 2 billion gallons of water per year worldwide. Convert that amount into dollars and see how astonishing the amount of money it saves annually.

How to use the dual-flush toilet?

The use of the dual flush toilet is as easy as eating a piece of cake. You may have observed that there are two flushing buttons at the upper portion of the toilet tank lid. The unique feature is that here you can use this flushing in two different ways; those ways are,

  • Small button for evacuating the liquid waste 
  • Larger buttons for evacuating solid wastes like poop, tissue paper, sanitary napkins, etc.  

It is as simple as it gets. When you are urinating, press the small button to dispose of this liquid waste. When you have finished defecation, press the larger button for evacuating the waste, and the system requires the same for disposing of sanitary napkins and solid tissue papers. This system has a big advantage: larger Trapways make it easier to dump away all the clogs and impurities. It also keeps the toilet surface clean for a longer time. That’s how you can use two different flushing systems for different kinds of waste.

What happens while pressing both buttons simultaneously?

As discussed earlier, the dual flushing system uses two different flushing technologies in the same toilet. But what happens if you press both buttons at the same time? We will come to this after discussing the dual flushing technology. toilet push button flush

The traditional single-flush HET toilets use almost 1.6 gallons of water per flush, and the normal toilet uses more than 3 to 5 gallons of water per flush. Now, if we talk about the dual flush system, the small flush uses less than 1 gallon of water per flush, and on the other hand, it takes about 1.25 to 1.6  gallons of water per flush for solid waste.

You can press both buttons simultaneously if you have more dense and heavy-duty waste. That allows more water to flow into the toilet tank. Practically one and a half flush has been initiated by pressing both buttons simultaneously, and the net amount of water must be 2 to 2.5 gallons of water per flush.

Final Verdict

The dual-flush toilet is amazingly eco-friendly that can save a gargantuan amount of water per year. If you wisely use this toilet, you save tremendous water and a huge electricity bill. Though there are different flushing systems, it will cause no harm to the toilet if you push both buttons simultaneously. But people usually don’t do that if there is no heavy-duty waste material. So use this type of toilet prudently to acquire maximum benefit out of it.

Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.


  1. Our family includes members ranging in age from 4 to 80. The 4 year old and the 80 year old both have problems depressing the flush buttons. Can the buttons be adjusted in some way?

    • It is not an easy thing to do. But, you can call a professional plumber. They will see the toilet’s flush button and can try to find a way to adjust the button.

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