What Are The Components Of A Toilet Tank?

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Last Updated on January 12, 2023 by acechapman

Two main components of a toilet are a tank and a bowl. The tank is typically on top of the bowl to allow water to flow from it to the bowl by gravity when flushing.

A toilet tank’s main purpose is to provide enough water for the bowl to flush the toilet. To enable flushing to occur, you must pour large quantities of water into the bowl immediately to activate the siphoning effect.

A toilet tank replaces the need for water pressure because most homes do not have enough water pressure. However, tankless toilets don’t have tanks.

Types Of Toilet Tank Parts

Flush Mechanism

  • Tank Lever
  • Toilet Flapper
  • Flush Valve

Refill Mechanism

  • Fill Valve
  • Toilet Float
  • Refill Tube

There are two types of toilets available: one-piece and two-piece. Two-piece toilets are more complicated than single-piece toilets, and can also leak more easily.

components of a toilet tank

Components Of A Toilet Tank

You can find a majority of parts for a toilet tank in any location. This is why companies such as Fluidmaster or Korky sell toilet tank parts, even though they don’t make toilets.

You can purchase a replacement tank part directly from the manufacturer. It is helpful to know the model number of your toilet. You can do this by removing the toilet tank lid and checking the wall opposite you. There will be a stamped or molded number for the toilet.

One part of the toilet can be replaced or the whole tank can be rebuilt. If your toilet isn’t flushing as well as it used, you should choose the former.

Let’s now look at the components of a toilet tank.

Tank Lever

A tank lever, also known as a toilet handle or flush handle, is a lever or handle located on the side of a toilet tank that is used to initiate the flushing action. When the lever is pushed or pulled, it activates the flush valve, which releases water from the tank into the bowl and down the drain.

Tank levers are typically connected to the flush valve via a chain or linkage, and are designed to provide an easy and convenient way for users to flush the toilet. They come in different styles, shapes, and sizes and can be made of plastic or metal, and can be mounted on the left or right side of the toilet tank.

Tank Lid

A toilet tank lid is a removable cover that sits on top of a toilet tank. The lid provides access to the inside of the tank and covers the working parts of the toilet, such as the flush valve, fill valve, and overflow tube. The tank lid is usually made of porcelain or plastic and sits on top of the tank. It is usually attached by hinges or clips and can be removed by lifting it up.

It is important to keep the lid closed when the toilet is not in use to prevent children or pets from falling in. Some toilet tanks lid can be used as seat covers and they are usually available in different colors, styles, and sizes to match the toilet design.


A flapper is a mechanical seal that is located in the base of the toilet tank and controls the release of water from the tank into the toilet bowl during the flushing process. The flapper is typically made of rubber or similar flexible material and is attached to the flush valve at the bottom of the tank.

When the toilet is flushed, the flapper is lifted up by the flush handle or lever, and water is released from the tank into the bowl through the flush valve. Once the flushing process is complete, the flapper falls back down into place and seals the flush valve, preventing water from draining out of the tank.

Flapper Lift Chain

The flapper lift chain is a small chain that connects the flush handle or lever to the flapper in the base of the toilet tank. When the flush handle is activated, the chain pulls on the flapper, lifting it up and allowing water to flow from the tank into the toilet bowl.

The chain should be adjusted so that it is not too loose or too tight; if it is too loose, the flapper may not lift high enough to properly flush the toilet, and if it is too tight, the flapper may not be able to seal the flush valve properly, which can cause leaks.

Always ensure that the lift chain is not too tight. It should not be too tight or the flapper won’t open fully, leading to a slow flushing toilet. It should not be too tight or it could cause the flapper to come off and result in a running toilet.

Flush Valve

One of the most important components of a toilet tank is the flush valve. The opening in the bottom of the toilet tank that allows water from the tank to enter the bowl is called a flush valve. The diameter of flush valves is between 2 and 4 inches. The flush valve is topped by a flapper for the toilet.

Sometimes, a crack in the toilet flush valve can cause leakage between the bowl and tank. It takes longer to replace a toilet flush valve because it requires removing the toilet tank first.

Kohler toilets use a different type of flush valve. This is the canister flush valve. They use a canister that lifts completely during flushing instead of the traditional toilet flapper.

Overflow Tube

An overflow tube is a pipe or tube that is located in the toilet tank and extends up to the rim of the toilet bowl. It is designed to prevent the toilet tank from overflowing in the event that the flush valve becomes stuck open or the flapper or other mechanical seal fails to close properly.

The overflow tube is connected to the rim of the toilet bowl, so that if the water level in the tank rises above the top of the overflow tube, the excess water will flow out of the tube and into the bowl, rather than overflowing the tank.


The toilet tank to bowl gasket seals the area around the flush valve.

It seals the tank to the bowl and prevents water from leaking between them during flushing. This is a sign that the tank-to-bowl gasket (also known as a spud washer), has become worn.

The complete removal of the toilet tank is required to replace the bowl gasket.

Tank Bolts

You can also get toilet tank bolts with steel washers, nuts, and rubber washers. These washers are used to attach the toilet tank to a toilet bowl.

Modern toilet tanks are designed so that bolts are hung from under the tank in brackets, instead of through the toilet tank’s interior. This is done to prevent the tank from leaking. It is called the DryLock system installation method.

After years of use, toilet tank bolts can become loose or corroded, causing leaks between the tank and the bowl. It is important to replace them as well as the tank-to-bow gasket and, if possible, the flush valve.

Fill Valve

A fill valve is a device located in the toilet tank that controls the flow of water into the tank. It is responsible for refilling the tank with water after a flush and maintaining the correct water level in the tank.

The fill valve typically consists of a valve stem that extends into the tank, a float mechanism (such as a float ball or float cup) that rises and falls with the water level, and a valve seat that controls the flow of water into the tank.

When the water level drops after a flush, the float mechanism falls, signaling the fill valve to open and refill the tank with water. When the water level reaches the correct level, the float mechanism rises, signaling the fill valve to close, stopping the flow of water into the tank. Some fill valves can be adjusted to control the amount of water refilled during a flush, which can help to conserve water and reduce water bills.

Float Ball

A float ball is a cylinder-shaped plastic part of a toilet tank that connects to the fill valve via a metallic or plastic arm. It controls the fill valve’s opening and closing.

The float ball will normally be at the top of your tank if the toilet is full but not being used. The ball will fall to the bottom of your tank when you flush the toilet. This opens the fill valve, and water begins to flow again into the tank.

Once enough water has been added to the tank, the fill valve closes and the float ball stops. At that point, the toilet can be used again.

However, you will find float balls in old toilet tanks. A modern toilet will not have one.

You can replace your old ballcock with these floats. The new floats are easy to put together and come with a fill valve.

Float Cup

A float cup is a small, cup-shaped device that is often found in the fill valve of a toilet tank. It is attached to the fill valve and sits in the water in the tank. The fill valve controls the water level in the tank and the float cup is a part of this mechanism.

The float cup is designed to rise and fall with the water level in the tank. When the water level drops after a flush, the float cup falls, signaling the fill valve to open and refill the tank with water.

The toilet float is most likely the culprit if the water level in the tank or bowl seems too low. Learn how to adjust the toilet float and thus the water level in your tank/bowl.

Refill Tube

A refill tube is a small plastic or metal tube that connects the fill valve to the overflow tube. It is responsible for controlling the water level in the tank, and the refill tube is connected to the fill valve and is placed inside the overflow tube. Also, it is responsible for refilling the tank with water after a flush and maintaining the correct water level in the tank.

The refill tube is designed to be adjustable so that the water level can be set to the appropriate level for the specific toilet. The water level should be set so that it is below the top of the overflow tube, but high enough to allow the flush to function properly.

components of a toilet tank

Common Problems Of A Toilet Tank

These are the most common issues with toilet tank parts, and how to fix them.

The toilet Won’t Stop Running

If your toilet won’t stop working, 99 percent of the problem is in your toilet tank. Three parts of the toilet tank are always suspects. The three parts that cause continuous running of the toilet are the flapper, the float cup/cup, and the fill valve.

If the flapper becomes worn or if it isn’t sitting correctly on the flush valve because of mineral deposits, water can leak underneath the flapper and your toilet will continue to run.


If the flapper starts to wear out, replace it or clean it well if it is dirty. To remove any dirt, it is a good idea to clean the toilet tank every so often.

Not Enough Height Adjustment Of The Float Cup And Float Ball

You can determine the level of the water in the toilet tank by the floating cup/ball. More water fills the tank if you don’t adjust the cups/balls properly. The excess water fills the bowl, which will then flow back into the bowl via the overflow tube. This will result in the toilet running continuously.


Use a screwdriver to locate the screw nearest the floating ball/valve. To adjust the water level in the toilet tank, turn the screw one at a time. Counterclockwise to increase the water level. During this repair, close the water supply valve to the toilet.

Fill Valve Opens And Closes

The fill valve will open and close after the water has filled the tank. It may not function as it should and continue to fill the tank with water. It can also cause the toilet to run continuously if it reaches the bowl via an overflow tube.


It is possible to repair the fill valve, but it is best to replace it.

Water Leakage Between Bowl And Toilet Tank

There is a good chance your toilet leaks between the bowl and the toilet tank. The toilet tank to bowl gasket needs a replacement in this case. Also, replace the flush valve gasket and the tank bolts.


You should ensure that rubber washers contact the porcelain material in the toilet tank. If you tighten the bolts too tightly, the toilet tank will not crack.

The toilet Handle Stays Down After Flushing

After flushing, a toilet handle should spring back up. It connects with a chain lift, which then connects to the flapper. The handle drops when you flush. The chain lifts off the flapper by lifting it off the toilet valve. To flush, water runs to the bowl.

If the flush handle does not move, it is possible that the lift chain attaches to another part of the toilet tank.


Take off the lid of the toilet tank and inspect the condition of the flapper and lift chain. You can unhook the toilet tank lid if it tangles up.

Wrapping up

Today, the toilet is a marvel of technology that we take for granted. If some of the components of your toilet tank fail, you will suddenly stop trusting it. Call a plumber to find out if you need replacement parts for your toilet tank or to fix your toilet problem.

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