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Anatomy of a Toilet Explained

Posted On: July 19, 2021
Internal Plumbing Toilet

No home is truly complete without a functioning toilet. While these bathroom mainstays might be part of our daily lives, few homeowners take the time to truly understand the mechanics behind this essential plumbing fixture. Understanding the anatomy of your toilet can help you troubleshoot problems when something goes wrong. Not only will this provide you with an added sense of accomplishment, but you’ll also save money on plumbing repair requests if you know where to look and what to look for.

To help you better understand toilet troubleshooting and the underlying mechanics that make your plumbing fixture function, our team has put together a guide to the anatomy of a toilet.

If you still have trouble pinpointing the cause of your toilet troubles, don’t hesitate to contact Genz-Ryan Heating, Cooling, Plumbing & Electrical for the toilet repair service you need.

Take a Tour of Your Toilet

toilet parts labelled diagram

Let the tour begin! Remove the lid from your toilet and begin by closely inspecting the parts inside the tank. Most standard toilets come with the following features:


Located at the end of the lift chain is a rubber flapper that lays against the flush valve opening. In older toilets, you might see a tank ball located here instead. Regardless of whether you have a flapper or tank ball, the operation remains the same: When the toilet handle and lift chain lift the flush valve to send water into the bowl, the flapper is what stops the flow of water and prevents a continuously running toilet. If you’re experiencing a running toilet long after flushing, the culprit is likely a faulty flapper.

Float Cup

Newer toilets feature a float cup, a special device used to sense the water level in the toilet’s tank. The float cup also shuts off the water supply valve when the water has reached the appropriate level within the tank to prevent overflow. Older toilets might have a float ball instead. A float ball will be attached to a horizontal pivot arm that is attached to the supply valve, while a float cup is attached to the vertical arm of the supply valve.

Flush Valve

At the bottom of your tank, you’ll find what’s known as the flush valve. This device is typically connected to the vertical overflow tube and forms the opening where the water exits from the tank and into the toilet bowl during flushing. There should be a large, soft, O-shaped seal around the base of the flush valve to cushion the joint between the tank and the bowl.

Handle & Flush Rod

The handle and flush rod are responsible for initiating a toilet flush. Once you’ve located the handle, you’ll see that it’s attached to a horizontal rod connected to the lift chain or wire (more on that later). Sometimes, a toilet handle might become loose, which can be easily fixed with a simple tightening of the plastic or metal mounting nut inside the tank. To tighten, be sure to turn the nut counterclockwise as it is the opposite of the way nuts are normally threaded.

Lift Chain/Wire

When you lift the lid of your toilet tank, you’ll notice a chain extending horizontally from the handle. This is the lift chain that goes all the way to the bottom of the tank. When the flush valve is initiated, the lift chain lifts the valve to allow water to rush into the toilet bowl. If you’re unable to flush your toilet, a likely cause could be that your lift chain or wire has been disconnected or damaged.

Overflow Tube

Attached to the flush valve is the overflow tube, responsible for preventing water from overflowing if the supply valve doesn’t shut off. Any excess water will travel over the top of the overflow tube and down into the toilet bowl. If you have a running toilet, your overflow tube might be clogged or damaged, keeping the water level too high in your tank.

Refill Tube

This small, flexible tube is clipped to the top of the overflow tube in the center of your toilet tank. The refill tube is responsible for sending a small, steady trickle of water into the toilet bowl after the toilet has been flushed and needs to be refilled. This is how the water in your toilet gets replenished after each flush. It is also essential in keeping the bowl and trap sealed against sewer gases.

Shut-Off Valve

Located on the outside of your toilet near the water supply pipe, there should be a shut-off valve near the floor. The shut-off valve is usually located on the left-hand side of the toilet beneath the tank. This valve allows you to shut off water to the toilet if you need to make any repairs. Not all toilets have a shut-off valve installed, but it’s a good idea to have your plumber install one for added convenience in the future.

Supply Tube

Connected to the shut-off valve and water supply tailpiece on the bottom of the tank is the supply tube. This vinyl, plastic, or steel mesh tube is usually not responsible for any major malfunctions with your toilet. However, they can start to fail as they get older or if connections loosen over time.

Toilet Bowl

Perhaps the most easily recognizable feature of your toilet is the bowl. This is where all waste is collected and transported from your home through your main sewer line. The toilet bowl unit contains a curved trap structure that acts similar to a sink drain trap. This internal trap holds standing water and prevents sewer gases from entering the home. All the water you see in the bowl is actually the top mouth of this drain trap. When a drain clog occurs in your toilet, the likely culprit is the drain trap.

Water Supply Valve

Also referred to as the ballcock, the water supply valve is a vertical structure usually mounted on the left side of your tank. This is the part of your toilet that opens it up to a fresh supply of water to refill the tank at the end of each flush cycle. The valve closes again to shut off the water once the proper internal level is reached inside the tank.

Wax Seal

Underneath your toilet, you’ll notice a soft wax ring. This is what seals the connection between the bottom of your toilet and the drain trap opening in the floor. Creating an airtight, watertight seal, this wax ring keeps water from seeping out around the base of your toilet during flushing.

Genz-Ryan’s Twin Cities Toilet Services

Now that you understand the ins and outs of your Twin Cities toilet, you’ll be better prepared to troubleshoot your system when something goes awry. Of course, when toilet troubles persist, it’s a good idea to have a knowledgeable plumber you can call to set the problem straight.

Genz-Ryan offers the comprehensive toilet services that Minneapolis-St. Paul residents need exactly when they need them. Schedule toilet services in your home by contacting our team today!

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