One of the crucial elements of your toilet is the trapway or siphon outlet, which can either be concealed or exposed. So the main difference between an exposed and concealed trapway is their drain pipe design. The drain pipe of an exposed trapway is clearly visible, but a concealed siphon outlet is hidden.
But that’s not all! These two siphon outlets differ in how they look and ease of cleaning and maintenance. However, even with their differences, these siphon outlets perform the same job of allowing the movement of wastewater to the sewer.
So then, what are a trapway and its functions? Read on to find out what is an exposed and concealed trapway, and how each one looks. But before that, check the table below.
Table of Contents
Exposed vs. Concealed Trapway – Comparison Table
Below are the key differences and similarities of exposed vs concealed trapway to help you decide which is the best choice.
| Differences & Similarities | Exposed Trapway | Concealed Trapway |
| Design | Visible S-shaped pipe from the side | S-shaped pipe and bolts caps tucked away |
| Ease of cleaning | Relatively hard | Easy and fast |
| How it looks | Has visible ridges and curves | Smooth and sleek surface |
| Commonly found in | Standard toilets | Modern toilets |
| Sizes | 1 3/4 – 2 3/8-inches | 1 3/4 – 2 3/8-inches |
| Cost | Relatively cheaper | A little expensive |
What is a Trapway?
Also known as a siphon outlet, a trapway is a drain pipe or path inside the base of your toilet. This pipe is located at the back of your toilet and connects your toilet bowl to the sewer line.
Overall, there are three trapways, including exposed, concealed, and skirted. Each type has its own pros and cons. More so, the trapways come in various sizes to choose from for improved passage of waste.
Functions of a Trapway
Now that you know what is a trapway, what are the functions of this vital component of your toilet? Let’s find out.
Smooth Flow of Waste
The primary function of a trapway is to allow a smooth passage of wastewater from the toilet bowl to the sewage line. But how does this happen?
When the bowl fills, gravity usually forces water into the trapway. This causes it to overflow at the top, creating a suction. As a result, this allows the waste and water to flow out of the bowl.
Anti-clogging Agent
A trapway also minimizes the chances of your toilet clogging by creating an easy pathway for the waste. Thanks to its size, it can trap a lot of things that would clog your toilet drainpipe further beneath.
Keeps Sewer Gasses Away
The trapway is designed to keep a small amount of water at the toilet’s base after every flash. This water acts as a seal, preventing sewer gasses from entering the toilet bowl.
Adds Visual Appeal
In a bathroom where there is little going on, a trapway can create a visual appeal. It has an exciting look that is not only modern but also sleek.
Design of Exposed Trapways
As the name suggests, an exposed trapway is visible. This means you can see the pipe or outlet running along the side of your toilet. Typically, this trapway is common in standard toilets and features standard bolt caps.
But how does it look? It looks like an S-shaped pipe with more angles and curves. You can easily see the outline of the S-bend pipe from the side, which creates an exciting curvature.
Design of Concealed Trapway
A concealed trapway is one whose S-shaped pipe is hidden away. Therefore, you cannot see the tube running along the side of your toilet. Overall, a concealed trapway is common in contemporary toilet designs.
Unlike the exposed trapway, a concealed trapway has smooth sides at the back of the bowl. So, you should not see any ridges or even the outline of the S-shaped pipe.
Concealed Trapway Pros
This is because a concealed trapway offers several benefits over its exposed counterpart. These include:
Easy to Clean
The hidden S-pipe makes it easy to clean and maintain a toilet with a concealed trapway. You only wipe down your toilet since there are no ridges where dirt could hide.
Sleek Appearance
A concealed trapway gives your toilet a sleek appearance and a clean look from the side. Therefore, it is sure to add striking beauty to your bathroom.
Minimalistic Design
This trapway also boasts a minimalistic look designed to complement any contemporary-style bathroom. The reason being it does not have tons of details like an exposed trapway.
Typical Trapway Sizes
According to the American National Standards Institute (ANSI), a trapway should not be less than 1 1/2 inches in size. With this in mind, the typical trapway sizes or diameters range between 1 3/4 inches and 2 inches. These sizes enable better flushing and clog-free performance.
However, there also exist larger trapways than 2 inches, measuring up to 2 3/8 inches in diameter.
No Water in Trapway
A trapway should always have water at the bottom of the toilet. This water helps keep the sewer gasses away from surfacing into your toilet bowl. So, if there is no water inside the trapway, the sewer gasses will eventually escape into your house.
As a result, your house will be filled with noxious odors, and the gasses could affect your health. The good news? Fixing this issue is easy, just like fixing a broken toilet chain. You just fill the trap with water.
Key Takeaways
Exposed and concealed trapways have the same functions. Both siphon outlets allow waste to leave your toilet bowl and quickly head to the septic system. Even so, there are several exposed trapway vs. concealed trapways differences. With that said, here are some takeaways for you.
- The shape of an exposed trapway is clearly visible in the exterior ceramic or porcelain. However, a concealed trapway has its pipes covered, leaving a smooth surface.
- The different designs of an exposed and concealed trapway do not affect how your toilet works.
We hope you enjoyed another one of our comparison resource guides to broaden your toilet knowledge.