6 Ways to Adjust Water Level in Toilet Bowl

Did you notice that your toilet bowl water level is rising above or below the normal volume? This is a sign that some parts of your toilet are malfunctioning. The water level in your bowl can affect the flushing capability of your toilet.

While the toilet tank can be the culprit, most issues go beyond that. However, when you know how to adjust the water level in the toilet bowl, you will be able to tackle all these issues without spending too much.

Too low or too high water level in the toilet bowl are caused by several factors. Let’s quickly examine some of them.

Causes of Too Low Water Level in Toilet Bowl

1. Clogging of Vent Pipe

Virtually every American standard toilet has a vent pipe that is concealed from public view. It’s located inside the wall, with the extension running the roof upward. The primary function of a vent pipe is to move waste through the pipe.

The air pressure is controlled by the vent pipes, and it prevents you from seeing the burps or bubbles emanating from your toilet. A clogged vent will suck water through the trap into the sewers.

An obstruction in the vent will lead to air bubbles when you flush, which in turn, causes the low water level in the toilet bowl. Solving this might be beyond a DIY approach; you should talk to your plumber in this case.

2. Fill Tube Leakages

Fill Tube Leakages

The fill valve is usually located on the left side of your toilet, and its primary function is to refill the toilet tank after flushing. It comes with a rubber tube that connects the fill valve to the overflow valve.

Leakages sometimes occur in the fill tube that hooks into the overflow valve, and this impedes its ability to fill the toilet bowl.

Also, fill tube may be disconnected from the overflow tube and sometimes cracks after been exposed to moisture for a long time. Both conditions can result in a low level of water in your toilet bowl.

3. A crack in the toilet bowl

A crack in the toilet bowl

Most toilet bowls are made of porcelain. Sometimes your toilet bowl can develop a crack to different degrees. A hairline crack is not easy to detect, while a significant crack can cause flooding of your toilet. These will cause a reduction in the volume of water in the toilet bowl. Carefully observe your toilet bowl for a leak. You can also run your hand through it to detect a crack.

The use of a silicone seal is a temporary fix for cracked toilet bowl. Eventually, you will need to replace the bowl for a lasting solution.

4. Leakages from the toilet bowl base

Leakages from the toilet bowl base

Seeing water on the floor close to your toilet bowl often indicates a leaking base. This also causes a shortage of water in the bowl. You can correct this by inserting a new wax ring over the waste pipe, and seal it up with putty.

You can get additional information on how to fix a leaky toilet bowl base.

5. Unbalanced Toilet Float

Toilet float is the leading cause of fluctuation in toilet bowl’s water level. Toilet float comes in two forms, that is, the ball-and-arm and the cylinder type.

While this is a great concern, however, you can always follow the procedures listed on our previous post on how to adjust toilet float (insert link) to fix the issue.

Causes of Too High Water Level in Toilet Bowl

1. Too Hight Tank Water Level

Too Hight Tank Water Level

If your toilet tank has an excessively high water level, it will cause water to splashy over the overflow tube, which serves as the opening in tank’s vertical pipe. This part of the toilet is what prevents water from spilling off the toilet tank.

One of its functions is to drain water flowing into the toilet bowl down the overflow tube. Ensure to keep the water in your tank below an inch by lowering your tank water level through adjustment of the toilet float.

Your goal here is to maintain a balance. Getting this right will automatically correct the volume of water that goes into your toilet bowl.

2. Clogging


Clogging of the toilet drain is another issue responsible for too much water in the toilet bowl. The clogging may be partial or complete based on the number of impediments. A quick way to know if your toilet bowl has a clog is to pour a large bucket of water swiftly into it. Notice the pattern of draining. A normal drain means an absence of clogs, while no drain indicates that there is an obstruction to the flow of water.

In partial clogging, although the water in the toilet bowl may drain, it will be slower compared to one without clogs. You need to check your toilet trap for what can be a partial clog. It’s a curve-like structure underneath the toilet bowl.

If the water in the bowl rises to a specific level, it spills over the trap and trickles down the toilet drain. What happens in a partial clog is that water will be prevented from spilling over the main pipe. Thus, the water level in the bowl will be more than necessary. You can get rid of a partial clog by clearing it with a toilet auger.

How to Adjust Water Level in the Toilet Bowl

We have mentioned briefly different ways through which you can adjust the water level in your toilet bowl. They include:

  1. De-clogging the vent
  2. Sealing of Fill Tube Leakages
  3. Application of Silicone seal to a hairline crack
  4. Insertion of a new wax ring over the waste pipe
  5. Adjusting the toilet float

However, if the listed method fails, you may need to consider installing a new fill valve.

How to Adjust Water Level in Bowl by Installing a New Fill Valve

Here are the step-by-step guides you can follow to adjust water level in your toilet bowl through the installation of new valve:

Step 1: Determine the right fill valve to buy

Determine the right fill valve to buy

The type of toilet you use will determine the type of fill valve you will buy because what works comfort height toilet might not work in upflush toilet fill valve. You can do some research on the best fill valve for your toilet.

Step 2: Remove water from the toilet bowl

Remove water from the toilet bowl 1

Your toilet bowl must be completely free of water before you can install a new fill valve. Firstly, turn off the water supply to the toilet tank. Check the wall behind below the toilet to locate the external water valve. Turn the knob clockwise to have a firm close as that will prevent the water from refilling. Next is to flush the toilet continuously until there no longer any water in the toilet tank. Use a foam or a towel to soak up any remaining water in the tank.

Step 3: Disconnect and remove the old fill valve

Disconnect and remove the old fill valve

Locate two nuts outside the toilet tank. One connects the water supply line to the valve while the other is used in attaching the fill valve to the tank. Unscrew both nuts to detach the fill valve. You should be able to do that without any tools, but if it appears to be too firm, use a wrench to loosen the nuts. Carefully lift the old valve, including all its accessories, as well as the attached float out of the tank. You can either discard the old valve or keep it if you intend to repair it for later use.

Step 4: Install a new valve

Install a new valve

Put the new fill valve in its designated position by placing the base in the bottom of the tank through the hole. Ensure that other units sit firmly without any shaking or wobbling, and be sure that the valve is securely attached to the base.

Step 5: Reconnect the supply hose

Reconnect the supply hose

Fix the hose back to the valve’s base and reattach any washers back to the top of the small supply hose that connects to the bottom of the tank. Firmly screw the nuts back to guide against any water leakages when you power on the water source.

Step 6: Test the toilet flush

Test the toilet flush

Power on the water supply until the toilet tank is at the normal level. Press the lever to flush the toilet. Do it repeatedly until you are certain that the water is now at the proper level. Examine the water shut-off valve and also the new fill valve bottom for any water droplet. Retighten the connection if you feel any moisture. This should adjust the water level in your toilet bowl.


Setting the water in your toilet bowl at the right level can be a tricky task as several factors can lead to too high or too low water level. However, with the new knowledge that you have acquired on how to adjust water level in toilet bowl, you should be able to fix it yourself.

Remember, you can use any of these fixes based on the problem you diagnose:

  1. De-clogging the vent
  2. Sealing of Fill Tube Leakages
  3. Application of Silicone seal to a hairline crack
  4. Insertion of a new wax ring over the waste pipe
  5. Adjusting the toilet float
  6. Installing a new fill valve

Learned something new? Don’t hesitate to share with your friends that can need these solutions. Got any questions to ask? Kindly drop them in our comment section below.

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