Toilet Parts Diagram: How Toilets Are Put Together

If you’re repairing your toilet or aren’t aware of how the modern toilet works, we have a toilet parts diagram that you can use.

The modern toilet has been in use for nearly 150 years, and the simple and effective design shows no signs of obsolescence. If you’re repairing your toilet or aren’t aware of how the modern toilet works, here’s everything you need to know about the science behind this home staple.

How Toilets Are Put Together: Toilet Parts Diagram


Toilets aren’t thought of often for their ingenuity and their value in the modern home. However, the flushing toilet has been an irreplaceable fixture of the modern home since its invention in 1861 by Thomas Crapper. While the name may be funny, we owe a lot to Crapper and his invention for getting us out of the outhouse and into the home.

Since this invention, toilets haven’t changed much from their original design. While faraway countries may utilize bidets, aesthetic design differences, and even electronics to augment the experience of using the restroom, the overall function is the same.

We’ll be going over how toilets are put together—using toilet parts diagrams, and exploration of different types of toilets, and how to assemble a toilet. Hopefully, by the end, you can gain a new appreciation for a household device so often ignored.

Different Types of Toilets

While the modern flushing toilet will remain our central focus, it’s hard to discuss the inner working of these devices without first recognizing that there are several different types of toilets across the world.

In many parts of Asia, squat toilets are more thoroughly utilized than seated toilets. Squatting is widely seen as a more natural position to have a bowel movement since the body is less stressed in the lower back and more naturally positioned. These toilets can be quite intimidating to the uninitiated but otherwise function similarly to their western counterparts.

Of course, Japan needs to be noted in any type of toilet discussion for their efforts to make going to the bathroom a near-luxurious experience. Japanese toilets can often feature heated seats, bidets that adjust to the desired setting, and even LCDs to control the entire setup.

Japanese culture places a high desire for cleanliness—which is partially why the term “Kirei” can refer to both beauty and the state of being clean.

Each of the above examples relies mostly on the same design as American toilets—and each uses gravity to pull water down into the bowl and flush the toilet.

While specialty versions of toilets can be found in unique locations, like in planes or trains, the general sentiment and design always remain the same. For our purposes today, we’ll be looking at the anatomy of a standard American flushing toilet, as well as how to put one together from the ground up.

Anatomy of a Toilet

Any toilet parts diagram will show you that there’s more than just a tank and a bowl when it comes to modern toilets. Let’s break it down, point by point:

At the very bottom and underside of the toilet is the opening for the toilet flange, which allows for watertight passage of blackwater from the toilet into the sewage system. While the toilet flange itself isn’t a part of the toilet, it is also crucial for any successful operation.

Moving up from the large, flat base of the toilet, you’ll find the enclosed bowl. Most bowls come in either standard circular or oval shapes, and allow you to mount the lid and seat of the toilet to the back of the bowl via two small holes.

With these holes as well as the bolts utilized in securing the base, it’s important not to over-tighten any nuts of crews. While porcelain is generally strong, it is brittle, and too much tightening can lead to unsightly cracks and compromise the integrity of your unit.

The very back of the bowl of the toilet is typically a large feeder hole for the water flow. For most American two-piece toilets, this is where the base of the tank needs to be mounted. The tank mounts both into this hole as well as through two smaller side holes to bolt the two pieces together. We’ll be going over this assembly process a little later on.

The valves and rubber gaskets that hold these two pieces together will also connect to the bottom of the tank—where the flapper valve is found. The flapper valve is perhaps the most important part of the toilet and is what is lifted and shut when the handle is pulled to flush the toilet.

The flapper valve is connected via a chain to the handle, and once activated, will help hold open the flapper valve until the tank has fully drained. The amount of water alone (1.6 gallons in most residential units) performs the work of rushing into the bowl, and the weight of the water itself is what pushes the toilet contents over the P-trap pipe and into the sewage system.

The tank’s system of refilling itself is simplistic, yet ingenious. Once the water drains enough to lower a small rubber piece called the float ball, a valve triggers that releases water into the tank. At this point, the flapper valve has already shut and will allow the tank to fill without drainage.

Once the tank fills enough to raise the float ball, the toilet finishes filling, and the cycle is complete. A failsafe is also featured in most toilets, which will drain water through an overflow spout and into the bowl of the toilet. While this design won’t save any money in the water bill, it will certainly keep your restroom from flooding due to a faulty fill valve.

All of this toilet anatomy may seem redundant when trying to assemble a toilet, but it’s important to know the basic terminology and purpose of each component. Toilets come in various states of assembly or disassembly and knowing which piece goes where will be crucial in making sure everything’s in its right place.

Assembly of a Toilet

Putting together the toilet itself will depend upon the type of toilet ordered and the manufacturer. Most American toilets come in two pieces—the tank and the bowl. These will need to be cobbled together during assembly and effectively sealed with the valve’s gaskets.

For toilets that come in a unibody shape, squat toilets, or other fringe cases, using the toilet’s manual is crucial. In general, however, putting together a toilet goes a little something like this:

First, the bowl of the toilet is effectively mounted onto the floor via the bolts on the base of the toilet, and the placement of a new toilet flange. Next, the connective hole for water flow is filled with the rubber gasket and accompanying watertight rings. The tank is placed on top of the unit and is bolted together with the included nuts and bolts.

A level unit is important for long-term usage of a toilet, so both the bowl and floor, as well as the bowl and tank need to be secured evenly with firm tightness on the nuts. Too loose, and the seal between the tank and the bowl will be compromised. Too tight, and the bowl will shatter.

The tank is then assembled from the inside. In most units, the apparatus for filling the toilet will be assembled for you. The only thing left to do is to connect the float ball to the fill valve and measure out the ball chain to the appropriate length.

The chain needs to connect to the handle and the flapper valve but needs to be a specific length to keep the valve open when the toilet is flushed. Generally, this means attaching the value with about an inch of slack.

Once the inside is assembled, all that’s left to do is to connect to the water supply. Most toilets come with the necessary sealing rings, so assembly here is a simple matter of tightening the hose to the bottom of the tank and slowly opening the water valve—checking for leaks all the while.

The toilet will need to be flushed at least twice to get both the tank operating properly and the standard amount of stagnant water waiting in the bowl. Most issues with new toilets come from either improper chain length or an issue with a float ball that’s failing to trigger the fill valve.


That’s it; and toilet parts diagram or assembly instructions aside, this is the basic assembly and anatomy of the modern American toilet. This design hasn’t changed much from Crappers original patents, and for a good reason. The design is simple, effective, requires little maintenance from the end user, and lasts for decades when properly installed and maintained.

Knowing how toilets are put together often aids in repairs. Simple fixes like the replacement of the toilet flange or the flapper valve are made much simpler by a knowledge of how these pieces interact with the whole.

We hope that we’ve covered just about anything you would need to know about toilet anatomy, assembly, and basic bathroom repair.

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