How to Adjust Water Level in Dual Flush Toilet

As we advance our footsteps in new technologies it often turns out to be a bit intricating as we always look for a guide to answer our question like how to adjust water level in dual flush toilet? To understand these first let us go through the dual flush concept.   

Dual Flush Concept

A dual flush toilet is an advanced variation of the standard flush toilet mechanism first developed by a Japanese sanitary product manufacturer in 1960. It was designed as a revolutionary product, equipped with dual levers and built-in hand washer that rehash the water in the hand washer for flushing. 

The dual flush toilet mechanism became almost popular and is widely adopted in Europe, Australia, and Asia and they are being used in other areas as well. The increased environmental awareness, the government regulations, the rising cost of water and the availability of monetary incentives are making people around the world to switch over to dual flush and low flow toilet designs as the most attractive method in the present sanitation market. 

Dual Flush Mechanism

Dual Flush Mechanism

The mechanism of the dual flush toilet is designed with a push- button dual flush feature that release different volumes of water depending on whether it is a liquid waste or a solid waste. In addition, it also differs from conventional siphon flush toilets as the removal of these features also means that the toilet requires less water to operate. 

The standard toilets use siphoning action, a method that employs a high volume of water entering the toilet bowl because of the air that enters the tube as the flush is pressed which makes the system ineffective and drain a large amount of water to clean the solid or liquid waste. 

The construction of the dual flush technology is developed with two operating buttons on the cistern which release different volumes of water: one button delivers six litres and the other three. The larger quantity is designed to flush liquid waste. 

For effective cleaning, the bowl of the dual flush toilet is designed with a larger 10 cm trap way (the hole at the bottom of the bowl) allowing for water to come out faster and clear the bowl effectively. As there is no siphoning action involved, on per flush the system needs less water and the large diameter trap way makes it easy for waste to exit the bowl. 

Moreover, the half-flushes for liquid waste combined with the effective large flush treatment can save up to 68% more water than a conventional low flow toilet. The mechanism of the dual flush toilet uses a larger diameter trap way that works more effectively and clog less than the conventional siphon toilet. It needs less water to flush efficiently and save more water than a low flow toilet when flushing liquid waste. 

Adjusting of a dual flush toilet

Dual Flush Toilet

The dual flush toilet mechanism is great for those homeowners who want to use less water for sanitation in an efficient way and is equally concerned about the environment. This is also a cost-effective way of saving money on your water bill. It is also used as an effective technology in newly build bathrooms in some municipalities for proper water treatment. The question that has often been raised as to how to adjust water level in dual flush toilet?

Well, the toilets with dual flush mechanism have a button mounted on the top of the tank that allows you to pick the size of your flush. Compare to the old toilet styles it has been found that the current mechanism uses just three litres a gallon for a flush, while the older toilet styles used five gallons per flush and you can figure out the difference in savings by yourself. 

Now when you are dealing with a dual flush toilet you need to know how to adjust it as an owner of these eco-friendly toilets so that you can come up with a solution to tackle your own difficulties. 

step 1: remove the dual flush toilet lid

When you are dealing with these types of toilets the first thing you will have to do is unscrew the push button, located on the top of the lid, before lifting the lid off the dual flush toilet. Then try to unscrew the button counterclockwise. If that doesn’t, work or the button doesn’t unscrew, then press down on one of the flush buttons. This will help you to unscrew the flush button assembly. 

step 2: adjust the lebel

It is pretty simple to adjust the water level in a dual flush toilet. These toilets are constructed using an integrated float assembly that lowers and raises with the water level to control the water flow. The ring-shaped float device that fits around the fill valve in the left-hand side of the toilet. 

Depending on the valve there are two ways of adjusting the level of the valve. One way of adjusting is by screwing that sits on the top of the fill valve assembly. When you tighten this screw clockwise it lowers the water, while loosening it counterclockwise allows the float to rise higher as the tank fills. 

If you want to adjust the water level then press together the two sides of the lock that attach the float valve to the fill valve assembly rail mounted on the side. There is no need to be panic if the water level raises during adjusting the dual flush because that’s normal. The water will automatically shut off when it reaches its new water level. Likewise in the next step of adjusting if you are lowering the water level, you won’t see any changes until after the next flush. 

step 3: flush the toilet

The 3rd step involves flushing the toilet by pressing down on one of the buttons on top of the flush valve in the centre of the toilet. This will flush the water in the tank to exit and then refill. After doing so check the new level. Make further adjustments only if it is still not at the correct level. To check the adjustment flush as necessary. 

step 4: finishing

Once you are done with the necessary adjustment check the water level and replace the lid. Screw the dual flush assembly back in the right position and then press the buttons into place if you removed them. Now after completion keep the procedure in mind and make similar adjustment as an when required. 


The dual flush toilet is a high-efficiency toilet mechanism that not only saves water but also is cost effective and has a powerful flush that clog less. Despite the certain setback, it is one of the best options to retrofit a dual flush toilet when striving to make the water bathroom, plumbing more water efficient. 

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