What Are the Parts Inside the Toilet Tank Called?

You’re on the phone with your plumber because your toilet tank’s leaking and the plumber asks you to check the flapper, but you have no idea what that is. Toilet tanks are pretty much universal when it comes to their parts, which are not that many. So, what parts inside a toilet tank do we have?

Every toilet tank consists of a flush lever and valve, a fill valve, an overflow tube, and a float ball. Although some newer models of toilet tanks use different designs, like concealed tanks mounted inside a wall, they all have the same basic components.

What Are The Parts Inside The Toilet Tank Called?

If you want to know more about different toilet tank parts and what they’re used for, keep reading this article. When you’re done, you’ll be ready the next time your plumber calls.

1. Flush Lever

The flush lever is where it all begins.

This small lever is connected to a metal or plastic handle on one side; on the other, it’s connected to a thin metal chain.

There are tanks where the flush lever is activated by a button on top of the tank.

When you press the handle that is placed outside your toilet tank, the side of the lever that’s connected to the chain goes up.

This pulls up the chain, which brings us to the next part.

2. Chain

The chain is connected to the flush lever on the upper side and a flapper on the bottom.

When the flush lever goes up, the chain follows and lifts the flapper.

Toilet tank chains are mostly submerged under water, so they tend to get rusty and break easily.

Luckily, there are individual chains you can buy, and they’re easy to replace if yours beaks.

3. Flapper

From the top of a toilet tank, where the flush lever is, we arrive at the very bottom, where flappers perform what the toilet tanks are famous for—flushing water.

Flappers are small plastic flaps or lids on top of flush valves.

When they’re closed, water can’t leave the tank.

However, when the chain attached to the flapper gets pulled by the flush lever, it pulls the flapper with it.

This causes the flapper to lift, opening the flush valve.

4. Flush Valve

The flush valve is basically a hole with a pipe attached to it.

This pipe goes directly into the toilet bowl.

Once the flapper’s lifted from the flush valve, that hole is opened.

The sudden opening of the flush valve creates pressure, which pulls all the water from the toilet tank.

When all the water leaves the tank, the flush lever returns to its original position, causing the flapper to close the flush valve completely, and at that point, the water that’s filling the tank can’t leak out.

READ: Why Is My Toilet Water Cloudy After Flushing? (Easy Fix!)

5. Fill Valve and Cap

Okay, so the water’s just been flushed through the flush valve, and the tank’s now empty.

The flapper closes the flush valve, and that’s when the fill valve comes into play.

As you can imagine, based on the name, the fill valve’s job is to fill the tank with new water after the tank’s been emptied.

The fill valve is connected to the water supply system, which is usually behind toilet bowls.

The fill valve comes with a small plastic cap attached to the top, which is closed when there’s water in the toilet tank.

6. Refill Valve

Fill and refill valves are not the same thing, but I understand where the confusion might come from.

After all, fill valves technically refill toilet tanks with water. Anyway, refill valves are an important part of every toilet tank.

You see, refill valves are small tubes attached to the fill valve on one side and the overflow tube.

Once you flush the water, the refill valve sends a tiny amount of water back to the tank.

Before you ask yourself why that’s necessary, let me tell you that this process shouldn’t be skipped.

The reason why refill valves send some water back to the tank after flushing is to keep sewer gasses away from the tank.

If there’s something wrong with your refill valve, change it as soon as possible.

7. Float Ball or Cup

Nowadays, there are two different types of floats: float balls and float cups, but the principle is the same.

Floats, as the name suggests, float at the water’s surface in a toilet tank.

When the water level drops, floats fall to the bottom of the tank, and when the water is refilled, they rise with the water level.

Floats measure how much water is in a tank, so you want to make sure they are set at the right height.

Floats are connected to the fill valve, and they control the fill valve shaft.

When the water level drops, floats descend and press the fill valve shaft, which in turn starts refilling the tank with water.

Once the water reaches a regular height, floats release the shaft, which stops pumping new water.

8. Overflow Tube

Malfunctions can occur with floats, which can cause the water level can keep rising until your toilet tanks start overfilling and spilling water everywhere.

That’s why there’s a part called overflow tube.

Overflow tubes are hollow plastic tubes, and their purpose is to keep a stable water level in toilet tanks.

Imagine that your float ball broke and the fill valve was filling the tank uncontrollably.

The excess water reaches the top of the overflow tube that sits in the middle of the tank.

Since the overflow tube is hollow, all the excess water goes through the tube and into the toilet bowl.

Because of overflow tubes, toilet tanks can never get overfilled to such a level as to start spilling water from the top of the tank.

However, overflow tubes can’t help you if there are leaks from the flush valve.


There you go—those are the essential parts of any toilet tank.

As you can see, none of them are too complex.

The mechanism behind flushing a toilet is smart but simple once you understand what each thing does.

Next time you’re talking to your plumber, you’ll be able to properly explain what’s happening to your toilet.

Cheers, tools owners!

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Hi there! My name is Jack and I write for ToolsOwner. I have a passion for everything related to tools and DIY projects around the house. You often find me in my workshop working on new projects.