Understand How a Toilet Works

Toilets are a part of the bathroom that we take for granted, but they're actually a technological marvel that contain several components that work together to effectively dispose of human waste.

The Parts of a Standard Toilet

You're probably not familiar with the internal parts of a toilet unless you've replaced a broken piece to save money instead of replacing the entire toilet in a bathroom remodel. The internal parts can be divided into three main systems that you can see when you lift the tank cover.

The main systems are: the refill mechanism, the flush mechanism and the bowl siphon. Each main system works together regardless of how it looks. And the look might be different from toilet brand or toilet design.

The Bowl Siphon

The bowl is where you do your business. It's possibly the most crucial part of the toilet. There's nothing complicated about the bowl. Most are porcelain which is a type of pottery created from a special type of white clay. The bowl is made in two halves from liquid form and dried as greenware. The two halves are attached and then the bowl is painted with glaze and kiln-fired.

Attached to the toilet bowl is the siphon. The siphon empties the bowl contents into the sewer system. Even if your tank isn't working, it's possible to use and empty your toilet as long as you have a bucket of water.

Quickly pouring a bucket of water of at least two gallons in the bowl will cause the siphon tube to fill which then changes the air pressure and amount of air in the tube causing the water to be automatically sucked out of the bowl and to the sewer pipes. When the water is gone, air enters the bowl siphon tube again stopping the siphoning process with a gurgling sound.

The Flush Mechanism

The flush mechanism is a system that changes the air balance and water pressure in the bowl siphon without manually pouring a pail of water into the bowl. In order for the toilet to flush, water needs to be added to the bowl quickly enough to activate the siphon. This can't be done with a regular house water pipe so a tank with flush mechanism was designed.

The tank holds several gallons of water collected from a house water pipe. A drain connects the water in the tank to the bowl siphon and a flush valve covers the drain until the water is ready to use. The valve is attached to a chain which is attached to the handle you see outside the tank.

When you press the handle, the chain lifts the valve cover. The water in the tank is released directly into the bowl siphon typically within three seconds. The speed at which the water is released activates the siphon effect and the waste is sucked out of the bowl.

When the tank is emptied, the chain falls and the valve covers the drain opening again.

The Refill Mechanism

The flush mechanism will only work if there's enough water available to activate the bowl siphon. Once the valve seals the opening, enough water has to be brought into the tank again to be able to activate the siphon effect the next flush.

The mechanism is designed to react when a ball float (filler float) falls. This happens when the water level in the tank drops after a flush. This triggers the refill valve to send water in two directions. Some of the water goes into an overflow tube that sends water to the bowl. Some of the water goes into the tank. As the water level rises, the filler float also rises. When it reaches a certain height, it turns the refill valve off.

The toilet is designed so that even if the filler float becomes detached, the toilet won't overflow. Water will continue to run into the tank, but it will automatically go into the overflow and fill the bowl. When the bowl becomes too full, it'll drain itself into the sewer pipes with the bowl siphon.