How Does a Toilet Work?

We rely on toilets every day to remove waste from our homes, but how does a toilet work? Learning the basic mechanics behind this household fixture is surprisingly interesting because there’s more to it than pressing a handle.

Knowing how a toilet functions can help you troubleshoot common issues, like clogs or running water, and in some cases, you can repair these problems yourself. This guide breaks down the components of a toilet and explains the simple process that makes flushing, refilling, and waste removal possible.

Basic Components of a Toilet

Breaking down the parts of a toilet can help you understand how it works. Each component works together to keep the toilet functioning smoothly.

Tank

The tank is the large, box-like part at the back of the toilet. Its primary purpose is to hold water, which it uses to push waste from the bowl into the sewer system during flushing.

When you flush, water from the tank heads into the bowl, allowing for waste removal.

Bowl

The main section of the toilet where waste collects is the bowl. Its curved design holds water and creates a siphoning action during flushing. This siphoning pulls waste through the trapway and out of the toilet.

Flapper

The flapper is a small rubber piece at the bottom of the tank. When you press the flush handle, it raises the flapper, moving water from the tank into the bowl. After the water drains, the flapper closes to allow the tank to refill.

Fill Valve

Each time you flush, the fill valve refills the tank with water. It connects to a float, which rises with the water level and shuts off the valve once the tank is full.

Flush Handle

The flush handle is the lever on the outside of the tank that starts the flushing process. Pressing the handle lifts the flapper, releasing water from the tank into the bowl, and flushing away waste.

The Flushing Process

The flushing process removes waste from your home. Here’s a closer look at what happens when you press the flush handle after using the toilet.

Step-by-Step Breakdown of a Flush

1. Pressing the Flush Handle: Pressing the flush handle engages a chain or lever inside the tank, lifting the flapper. In short, the flapper is a rubber seal at the bottom of the tank that holds the water in place.
2. Water Rushes into the Bowl: Once the flapper lifts, water from the tank quickly flows into the bowl. This surge of water begins the actual flush.
3. Siphoning Effect: The water from the tank enters the bowl with enough force to create a siphoning effect. The curved shape of the toilet bowl helps create this effect by directing water and waste toward the drain.
4. Waste and Water Enter the Drain: The suction pushes the water and waste down the drain through the trapway, and they exit the toilet and move into the home’s sewer or septic system.
5. Flapper Closes: Once the tank is completely empty, the flapper moves back into its spot, sealing the tank again so that it can refill with water for the next flush.

Siphoning Effect

The siphoning effect is perhaps the most important part of the flushing process. The toilet bowl’s curved shape and the rush of water create a suction that pulls waste and water down through the trapway and into the sewer line.

This effect ensures the device removes all waste with each flush. Without the siphoning process, waste might stay behind, requiring multiple flushes or causing clogs.

Fortunately, the toilet’s design considers water flow, which is what makes it such an effective waste removal system.

How the Tank Refills

After each flush, the tank automatically refills to prepare for the next use. This process involves two key components: the refill valve and float and the overflow tube.

Refill Valve and Float

The refill valve controls the flow of water into the tank. The float, a buoyant device that rises and falls with the water level in the tank, is attached to the refill valve.

After a flush, the float drops, signaling the refill valve to open and allow water to flow in. As the water level rises, so does the float.

Once the float reaches a pre-set height, indicating the tank is full, it triggers the valve to close. This step stops the flow of water. The refill valve and float combination fill the tank with just the right amount of water for the next flush.

Overflow Tube

The overflow tube is an important safety feature that prevents the tank from overfilling. If the water level in the tank rises too high due to a malfunction or misadjustment, the excess water heads to the overflow tube, which leads to the bowl.

This device prevents the water from spilling out of the tank and flooding the bathroom. The overflow tube helps balance water levels and safety during the refill process.

Water and Waste Removal Process

Trapway

The trapway is the S-shaped pipe at the toilet’s base that helps with waste removal. Its curved design allows water and waste to exit the toilet while preventing sewer gases from coming back into your home.

The standing water in the trapway acts as a barrier, sealing off unpleasant odors from the sewer or septic system. When you flush, the siphoning action forces waste and water through the trapway and down the drain.

Connection to the Sewer or Septic System

Once the waste exits the trapway, it moves through various pipes that lead to the New York City sewer system or a septic tank, depending on your home’s setup. These pipes transport the waste, using gravity and water flow to push it along.

In a sewer system, the waste eventually reaches a treatment facility, while in a septic system, it is processed on-site.

Get Professional Help With Your Toilet

Call Sanitary Plumbing

While it’s possible to address some toilet problems yourself, others will require professional assistance. That’s where Sanitary Plumbing can help. We can handle your toilet repairs or even place your toilet as part of your bathroom renovation. Call us at 212.734.5000 to learn more or book your toilet installation appointment online.