What Causes Low Water Level in the Toilet Bowl?

No matter how small or large, an essential element like the toilet needs to function perfectly in any bathroom. Any fault in the toilet bowl needs to be fixed immediately. The water level in the toilet is something we need to pay close attention to. Surely, you have already realized that every time there is something wrong with your toilet, most of the time, it has to do with the level of the toilet water. The best way to solve the problem in question is to fully understand the cause to repair it.

Low water level in the toilet bowl

So, what causes low water level in the toilet bowl? The most common cause may be a damaged fill tube. This is a plastic hose that controls the water level.

Read on for more information on this and what you need to do to remedy the situation.

Have You Ever Wondered, What Causes Low Water Level in the Toilet Bowl?

Here are a few of the more common causes.

Refill Tube or Feeder Tube

The toilet has a tube that runs the length of the top of the faucet across the top of the overflow tube. You need to make sure this refill tube is properly connected to the overflow tube. This part of the toilet helps the water go directly to the toilet as your tank fills.

If the refill tube is not working properly, adjust it with the help of tweezers. Make sure you don’t over-tighten it. Using too much force could damage the toilet tube and tank. Find an in-between setting. The tube should be tight but not too tight.

Damaged Toilet Bowl

It is also possible that you have a defect with the toilet itself. If there are any cracks or holes in the toilet, it could cause a small bubble in the porcelain. When this happens, the manufacturer typically does not repair the blemish but instead places a porcelain patch over the hole. This is just a temporary fix.

Eventually, that repair will fail, and the water will start to leak out. The water leak will still allow the water level to be maintained in adequate amounts for the toilet’s proper functioning. The toilet will fill up completely after flushing, but a few hours later, the level in the bowl will have dropped significantly.

Rubber Plug

Another reason that the water level in the toilet is low is that the toilet float is tangled in the chain or some other problem. This could be causing the water to keep running. Anytime the rubber stopper cannot snap back to allow the tank to fill, the water level will never have a chance to rise.

Whenever this happens, there are a few things that can be done that will allow the plug to work the way it should again. First, it is advisable to check the length of the chain. If the chain is too long, it could get caught in the float arm or get between the plug and the hole. On the other hand, if the chain is too short, then the cap will not be able to close completely.

How Do I Fix the Low Water Level In the Toilet Bowl?

Fix the low water level in the toilet bowl

When there is not enough water in the tank, the discharge power may decrease, causing an unwanted toilet clog or a blockage at some point. Fortunately, this toilet problem is not difficult to solve. A higher or lower float can usually be set by hand or with a screwdriver in a few minutes, without the need to call a plumber.

If you’ve identified the problem, try the following troubleshooting steps:


Remove the lid from the toilet tank. Lift the lid and, being careful not to damage it, place it on a stable and secure surface. Now you can access the flush system inside the toilet tank.


Check the water level in the tank. Generally, the water level should be 2.5 to 5 cm below the toilet fill valve and overflow tube for the toilet to function properly. If the level is less than this amount, you will see that the water level is experiencing a significant imbalance and you may have a toilet problem.


Turn off the water supply line to stop water flow. Remember to always close the stopcock of the toilet every time you go to make a toilet repair. This will prevent the water tank from filling automatically and allow you to do the job more efficiently.


Examine the float mechanism and fill valve. Check that the rinsing systems are in optimal condition. If you notice obvious damage or defects, you may need to call a plumber to repair or replace the part with a new one.


Check the height of the float. The float inside the toilet is a plastic ball attached to a metal arm. It is located on the top of the fill valve. The float must be right at the water level. If not, it could be broken or misplaced. If you see it’s too high or too low, adjust the height with the help of a screwdriver. You will find the screw at the top of the toilet fill valve. If you turn clockwise, the toilet bowl water level will rise and if you turn counterclockwise, the toilet bowl water level will decrease.

Once you’ve fixed the problem, refill the tank and see if the toilet water level has risen.

How is the Water Level Adjusted in a Dual Flush Toilet?

Lift the lid to the toilet water tank

Double flush toilets save your water consumption and, therefore, your money. They have two separate buttons for flushing the toilet. To adjust the water level in your dual flush toilet, it is unnecessary to remove the water from the tank. You only have to flush the toilet when you test the changes.


Remove the lid from the dual flush toilet tank and place it on a safe and stable surface. Under the tank, you will find two rods that connect to the flush buttons. Be careful not to damage these rods.


Locate the float adjusting screw between the fill valve and the dump valve. Turn the adjusting screw clockwise with a screwdriver to raise the water level to the indicator line on the inside wall of the tank.


Put the lid back on the tank and do a test with the flush buttons. Remember that the small button is for liquid waste, and the larger button is for solid waste.

Frequently Asked Questions (FAQ)

Still have lingering questions? Check out our brief FAQ below for more answers.

How do I adjust the water level in my American Standard toilet?

The water in your American Standard toilet should be now lower than half an inch below the top of the overflow tube. If the water is lower than this, you need to start raising the water level by turning the top screw on the water control counterclockwise. Once adjusting the screw, you may need to flush the toilet to get the water level to rise to where it needs to be.

How do I fill my toilet bowl with more water?

To fill your toilet bowl with more water, you can simply add water to the toilet tank until it reaches the top of the overflow tube. A gravity flush is another method you can use. You need to pour around 1.6 gallons of water into the toilet bowl very quickly for this method.

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