What Are The Possible Problems With Dual Flush Toilets?

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Last Updated on September 26, 2022 by acechapman

The most common problems with dual flush toilets are water running constantly, leakages, faulty flush mechanisms, water level problems in the tank and bowl, and water leaking.

Here are the details and steps to fix them. Find out about the disadvantages of double-flush toilets.

Dual Flush Toilets Problems

Flushing Does Not Stop Water from Running

If water is constantly flowing or filling up the toilet tank, it is likely that water is leaking through the flapper of the flush valve or that water is entering the overflow tube. You might not be able to see a leak immediately.

You can quickly tell if the water is leaking into the toilet bowl by adding a few drops of dye or food coloring to the tank.

If colored water is leaking into the toilet bowl, it is likely that the flapper or flush valve is the problem. However, if water remains clear in the bowl, the problem may be with the fill valve system or the overflow tube system.

If the water is leaking into the bowl, check to see if there are any of these issues.

  • A worn flush valve seal at the base of the center canister is the main reason why a dual flush toilet leaking occurs. Follow the manufacturer’s instructions to remove worn parts.
  • Flapping or misalignment of seals or flappers can also lead to constant water flow in standard and dual flush toilets. The rubber or silicone pieces can become porous and brittle over time.
  • To keep the overfill tube secure, zip ties can be fitted to most dual flush toilets.
  • Some functions of the flush mechanism may be affected by foreign elements, including dust, broken pieces, or other debris.

Water debris can cause problems such as failure of the valves or flapper functions on dual flush toilets. They are supposed to press against one another to create a perfect seal. However, if there is any debris between them, compatibility can fail and leakage happens.

Faulty Flush Mechanism

The dual flush toilet lever or buttons could fail because of a problem with the tank or directly. If the toilet isn’t flushing, check the flush mechanism. If the flush valve chain is not attached to the flush lever or flush ball, the toilet will not flush. The flush ball will lift when you flush the toilet if the chain is not too loose.

If the toilet isn’t flushing properly, adjust the water level by using the floating float. You can allow the tank to be filled faster and full pressure will be applied. To check if flushing is easier with the higher pressure,

To reduce the amount of noise generated by the toilet when it flushes, close the water supply valve. You can test flush the toilet and adjust the pressure until it is satisfied.

Water Level Problem In The Toilet Bowl

The cause of a toilet bowl that is higher than normal or fills up with water after flushing may be a clog in its drain.

A bucket of water can be used to test the condition of your toilet bowl. If it is high, it indicates a complete clog. If it drains slowly, it will indicate the size of the problem.

Some toilets won’t overflow if there is a blockage in the drain. However, others will overflow even if there is just a small blockage.

The main concern when the toilet bowl is overfilled with too much water is that water can run off the bowl’s edge and onto the floor. This could pose a risk to your health and cause structural damage to your house.

It is likely that it is near the bowl if the obstruction is severe. You can remove the obstruction if it is visible from your bowl. Make sure to wear safety gloves. To unclog drainage pipes, you can use a toilet plunger if it is too far away.

If the plunger method fails to clear the clog completely, or you have a partial blockage, an unclogging auger can be used to do the job. A strong, flexible wire can be used to improvise.

To confirm if the problem persists, flush the drain at the end. If the water level is not normal, you should consult a professional.

A rare problem is the lower water level in the bowl.

Low pressure in the toilet drainage system could cause this. Poor plumbing can lead to a ‘sucking effect’ that keeps the water level low.

problems with dual flush toilets

Problems With The Toilet Tank’s Water Level

If the water level in the cistern is higher than it should, it can lead to excessive water consumption and increase your water costs. Extra water in the bowl could be caused by a low water level or an obstruction in the drain.

A damaged or broken fill tub is the most common cause of low water levels. The water stops flowing before the tank can fill completely.

Many toilets have the ability to adjust the water level. Adjusting the water level in a dual flush toilet is easy. An integrated float assembly controls the water flow. It rises and falls according to the water level. The float is a circular device that fits around the left-hand fill valve of the toilet.

There are two ways to adjust the level depending on the valve. The screw is located on the top of the fill valve assembly and is used to reduce the water level.

You can press the sides of the lock connecting the float valve and the fill valve assembly rail to adjust the water level.

Water may be seen filling the tank when you increase the water level in your dual flush toilet. This is normal and not a reason to worry. The water level will be adjusted to turn the toilet off. The situation will remain the same until the next flush, so lowering the water level won’t affect it.

After you have made all the changes, flush the toilet and inspect the new level. Make more adjustments if it’s not at the correct level. Check it as often as necessary.


Dual toilets can clog more than other types of toilets. This is especially true if they are connected to a waste system that was not specifically designed for them.

This is because traditional flush toilets flush a lot of wastewater. They can also work well on drain pipes that have a small diameter. If you install a dual flush toilet on a drain with such a small diameter, it’s likely to clog up quickly or frequently.

You should avoid clogging by not flushing any foreign substances that are not able to dissolve in the water or be broken down quickly.

You can reduce the chances of someone flushing foreign products by placing a garbage container in the bathroom, preferably next to the toilet. Encourage everyone to dispose of foreign materials like paper towels, diapers, and cleaning & facial tissues.

Even though it may seem to be efficient in flushing all the waste from the bowl, you should still avoid flushing solid waste with low-volume options.

Flushing too much waste at once can cause clogs and blockage of the drain pipes. To avoid clogging, flush the toilet twice.

Compatibility with the plumbing system could also cause clogging. This is because the drainage systems that were in place before the current one are not designed to handle large volumes of water or high speeds to drain solid waste.

Installing a dual flush toilet on an old drainage system could lead to clogging because the little amount of water used might not be enough to push the waste along the pipes.

problems with dual flush toilets

Dual Flush Button Dilemma

Many dual-flush toilets have buttons instead of handle levers for flushing. They are usually located at the top of the toilet tank or cistern, which can prove inconvenient for children.

Guests who have never used dual flush toilets may be confused by the non-clear labeling of the high and low-volume flush buttons on every model. It is possible for guests to be shown around the equipment.

For the elderly or people with disabilities, it might be difficult for you to press certain buttons. Sometimes buttons can become stuck and cause the toilet to stop working, resulting in increased water consumption and higher costs.


Dual-flush toilets should be cleaned more often than your regular toilets. This is because each flush leaves less water inside the bowl. Some residual may remain in the bowl if you choose the low volume option for several models. Dual flush toilets require more frequent cleaning.

Toilets can get stained faster than regular-flush toilets. If you have a dual flush toilet, you will need to clean it more often.

Increased Toilet Repair Prices

Dual-flush toilets used to be more expensive than single-flush toilets when they first appeared. However, you can now get both toilets for around $100 if your focus is on the basics. However, repairing a dual-flush toilet may be more expensive. Dual-flush toilets have two flushing mechanisms, so there is twice the potential for problems. While this is not a major issue for DIY projects like replacing a flapper, it can be costly if you hire a plumber.

Dual Flush Toilet Disadvantages


Dual-flush toilets are more expensive than other toilets. These toilets are more expensive than regular toilets. Both the installation and purchase costs will be higher than for a regular toilet.

Dual-flush toilets are more expensive than other high-efficiency designs. Dual flush toilets are becoming more popular due to their efficiency and ability to save water. They are becoming more affordable and therefore more accessible to the general public.


Dual flush toilets with handles can confuse those who use standard single-flush toilets.

Wrapping up

These are the most common problems you might encounter with dual flush toilets.

These issues are unlikely to happen in a new toilet. They may develop over time depending on how often you flush it, how clean it is and how frequently you keep it maintained.

Each toilet will have its problems sooner or later, but it is worth learning about these issues and how to fix them.

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