toilet troubleshooting - low water level

Adjust The Water Level In Your Toilet Bowl (It’s So Easy!)

One of the most common toilet problems is excess overflow, which means that you or your plumber will need to adjust the water level in your toilet bowl.

It often occurs because the water level in the tank is not balanced correctly. The water level should be a half-inch or less below the overflow tube. When your water level is not balanced, one of two things will happen:

  1. Water will run into your toilet bowl constantly because the water level in the tank rises above the overflow tube.
  2. Your toilet won’t flush fully because the water level is too low. 

Luckily, with our help, you can fix either of these two problems yourself with a little know-how and maybe a flathead screwdriver.

Adjust water level in toilet bowl - inside of toilet tank illustration
Refer back to this illustration — the inside of a typical toilet tank — to determine the parts you will be working with while adjusting the water level in your toilet bowl.

First: Determine the Flushing Mechanism

There are many types of flushing or float devices.

For example, old toilets that haven’t been upgraded might still be using a metered fill valve. It does not use a float to control the water level in the tank. It’s doubtful you’ll run across this type.

In some newer toilets, you will find a floatless system. These are anti-siphon valves that can sense the pressure so they don’t use a “float” (such as the rubber/plastic ball we’re all used to). But they’re more expensive and not quite as reliable.

In this article, let’s focus on two in particular as they are still quite common: a ball-and-arm float and a float cup (or cylinder).

1. Ball-and-Arm Float

A float “arm” looks like a balloon or ball attached to the end of a metal rod (the rod is named the arm). Hence the name ball-and-arm float. Usually, the float is made of black rubber, but it can be made of other materials as well. Plastic has become a common material over the years.

This type of float has been around for many years. Although they’re being replaced more and more with new models, they’re still everywhere you look.

Adjust water level in toilet bowl - ball and arm style
This is what a ball-and-arm style flush mechanism looks like.

2. Cup Float

A cup float (also called a cylinder float) is the part that is wrapped around the refill pipe rather than on the end of a metal arm. It moves up and down the refill pipe (kind of like a telephone line repairman moving up and down a telephone pole) based on the water level.

Just like the ball float above, the cup moves up and down based on the level of water in the tank. When you flush, the water leaves and the cup drops down. As the water level rises back up, the cup floats back up. That’s the only difference between a float ball-and-arm and a cup float.

Adjust water level in toilet bowl - floating cup style
This is what a floating cup style flush mechanism looks like.

Second: Adjust the Floating Mechanism

Before you adjust the water level in the toilet bowl, you first need to adjust the float arm, the float cup, or the metered fill valve (depending on which one you have).

1. Ball-and-Arm Adjustment

If the arm is metal, you can bend it either up or down to raise or lower the float.

On plastic arms and some metal arms, there will be a knob at the ball cock (see diagram) where the arm meets the vertical pipe that supplies water back into the tank.

Be sure that the float rests halfway in the water. If it is covered by water, the float may be leaking and will need to be replaced.

2. Cup Float Adjustment

As described earlier, a cup float has its float situated on the intake pipe instead of on the end of a metal or plastic arm.

To adjust the level of the cup float, find the metal clip that holds the cup in place (it’s located along the refill pipe). While squeezing the clip, move the cup to the desired level and release the clip.

Here’s an easy-to-understand video on fixing this problem.

Third: Adjust Water Level in Toilet Bowl

Now you’re ready to balance your water level. Your screwdriver might come in handy on this final part of the process. And you might have to experiment a bit to get the water level balanced just right.

Check the level of water in the tank. It should be a 1/2-inch or less below the overflow tube.

Now, adjust the water level up or down accordingly, and flush the toilet to check that the level is balanced and one-half inch below the top of the overflow tube.

Repeat until you get it just right. That’s it!


If you’re like me, you’ll agree that having a quiet, non-leaking toilet is important enough to learn how to take care of problems when they first appear. It will save you time, money, and frustration when you need that toilet the most.

The toilet is the most common household water waster. A badly leaking toilet can waste nearly 80,000 gallons of water a year. While repairing a leaky toilet is a major water conservation project, it is a simple plumbing project.

Call 1-Tom-Plumber

1-Tom-Plumber repairs and installs toilets and other bathroom-related fixtures and drains. So if you need help, don’t hesitate to contact or call us at 1-866-758-6237.

We immediately respond to any of your emergency plumbingdrain services, or water damage problems. We also have specialists who excavate, repair, and replace broken sewer lines.

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