technician working on toilet tank

How a Toilet Functions

A Toilet is a rooted vessel consisting of a large bowl connected to a tank and flushing system which usually flows to a sewer or septic tank. Having knowledge about the functionality and components of your toilet can always be useful to help save you money in the future.

When pressing the flush lever on the toilet, a chain is pulled upwards lifting the flapper valve and releasing the water from the tank. The water then flows through the rim holes into the bowl allowing what’s inside to flow down into the drain below. The flapper then falls back to the bottom of the tank, sealing the siphon. Once that happens, the tank will begin to be refilled and the toilet can soon repeat the flushing process.

Toilet Tank Parts You Should Know

Now that we have a better understanding of how toilets function, it's time to break down each of the individual parts.

Fill Tube

The fill tube connects the fill valve and overflow tube. As the fill valve is refilling the tank, a little bit of this incoming water flows from the fill valve, into the fill tube, and then into the overflow tube, which dumps clean water into the bowl.

Overflow Tube

This tube makes sure that any excess water from the tank doesn’t overflow. Also if the fill valve malfunctions or breaks.

Fill Valve

This valve controls the flow of water into the tank of your toilet. It is usually mounted on the left side of the toilet tank, with a tailpiece that extends through the bottom of the tank where it attaches to a supply tube that runs to the shut-off valve. It also helps to control the water level in the tank. There are two types of fill valves:

Float Fill Valve

Also called a bobber or just fill valve; this valve has a floating light weight ball in the tank that rises with the water and shuts off water flow when the tank is full. It is connected to the fill valve by a float arm.

Floatless Fill Valve

This fill valve uses a pressure-sensing mechanism to operate the inlet valve. This valve is attached to the bottom inside of the tank, which means it operates underwater.


The usually rubber seal that suctions between the tank and the bowl and lifts when you flush, allowing clean tank water to fill the bowl.


An arm inside the tank that has a chain connected to the exterior handle as well as the flapper. When the handle is activated, the arm lifts the flapper on the inside.


The tank that sits on the back of the toilet for water storing slightly above the bowl.

If you ever need additional assistance with ANY of your toilet functions, don’t hesitate to reach out to Prometheus Home Services LLC. We pride ourselves on quick responses, positive attitudes, great work and up-front pricing!

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