One Piece Vs Two Piece Toilet: 10 Pros and Cons

Choosing between one-piece and two-piece toilets can be harder than you think. That’s because there are more factors to consider than simply how many pieces it has or how it looks. I have studied both types in detail, so let me break it down for you.

So, which is better, one piece or two piece toilet? Overall a one-piece toilet is better than a two-piece toilet. A one-piece toilet looks stylish, is smaller in size, easy to maintain and comes with a superior design and finish. However, a two-piece toilet is more affordable, widely available and if damaged, either the tank or bowl can be replaced individually. Flushing performance and durability wise both types are equal.

However, it’s better to have a thorough understanding of their pros and cons. This way you can make sure you’re getting exactly what you want for the price you are paying. So, let’s dive right in.

Construction

The “water closet” or toilet as we know it, has two main parts: the bowl and the tank. The key difference between a one-piece vs two-piece toilet is the way in which these parts are attached.

In the traditional two-piece toilet, the bowl and tank come separately. When you install, the tank is placed on the bowl and coupled together with fittings. (Therefore, it’s also known as a “close-coupled toilet”). Even in the best designed two-piece toilet, you can notice this clear separation between the tank and the bowl.

On the other hand, a one-piece toilet comes with the tank and bowl fused into one solid unit. There is no seam between the two parts. (So, they are called “single piece toilets”).

Usually, one-piece toilets have a skirted design that hides the contours of the toilet trapway and gives it a streamlined appearance. (Trapway is the “S” shape bend at the back of toilet bowls. It holds some water in the toilet bowl and stops the sewage smell and gases coming out of the toilet drain pipe from the sewage system. In siphon flush toilets, it also acts as a siphon vacuum)

Regardless of whether its one or two-pieces, the internal mechanisms of both toilet types are almost identical.

Aesthetics (Design and Looks)

Design and appearance wise one-piece toilets are much better than two-piece toilets.  It is the main reason why many people pick single-piece toilets. And one-piece toilets come in many attractive designs and shapes.

The seamless, continuous design of one-piece toilets looks very modern and stylish. Most one-piece toilets also have a skirted toilet bowl that conceals the trap-way. This makes them look contemporary and very elegant. It adds a luxury appearance to your bathroom decor.  

On the other hand, the design and appearance of most two-piece toilets are traditional, average or even ugly.  They have more corners and grooves and display the contours of the trapway.

Cheaper models of most two-piece toilets and even some one-piece toilets are designed in such a way their innards are still covered in porcelain, but the shape of their trap way is visible. Such toilets don’t look as attractive as those with a skirted design.

Looks-wise, I feel comparing a one-piece to a two-piece toilet is like, comparing designer wear to normal clothing. In most models the difference is huge. But there are a few toilet models where you can get a one-piece or two-piece toilet with the same design and look.

Ease of Cleaning

Cleaning wise too one-piece toilets are better than two-piece toilets.

There’s no gap between the tank and the bowl of a one-piece toilet. Therefore, dirt or grime cannot get collected there. This also prevents mold and bacteria growing between them.

Again, in one-piece toilets, the skirted bowl outer surface is smooth, flat and gently curved.  There are no nooks and grooves.  Therefore it has fewer hard to reach areas.

But it’s harder to clean the nooks and crevices of two-piece toilets. The likelihood of dirt and germs collecting up in them is higher.

So I find the one-piece toilet much easier to clean and maintain.

Durability

Generally, I have found one-piece toilets are built to a higher standard and have better quality parts and finish. So they are more durable.

But let’s consider the internal mechanisms like the flushing system. Here, durability depends on the quality of the product and the manufacturer.

In one-piece toilets, you are likely to find better quality and longer lasting internal parts like flush valves, flappers etc. So one-piece toilets will function longer without problems or having to replace parts. (Note, eventually in any toilet you have to replace internal flushing parts due to wear and tear.)

But two-piece toilets can start leaking between the tank and bowl after the rubber gaskets become worn out due to age. Yet, the seamless design of one-piece toilets prevents such leaks. This extends the duration the toilet can function properly.

However, with proper care and use either toilet can last 40 or 50 years.

Size Differences

This is a much-argued topic when it comes to comparing one-piece vs two-piece toilets.

Considering the toilet bowl size, they’re both almost identical. There are all shapes and sizes of toilet bowls in both types. Even with height, both come in standard (15 inches from floor to seat) as well as comfort height (17 to 19 inches from floor to seat).

But most one-piece toilets have a more compact and shorter height toilet tank. This makes one-piece toilets appear smaller in size and gives it a low profile look. (This has now diverged into a new toilet segment called low profile toilets)

One-piece toilets tanks can be designed smaller as the tank sits directly on top of the bowl. The tank doesn’t have to be secured using other supporting structures. In the two-piece toilet, more space and structure is needed to provide support to the tank. That’s the reason one-piece toilets look more compact compared to two-piece toilets (Especially, in height from floor to tank top and sometimes front to back as well).

One-piece toilets are usually chosen for bathrooms with smaller square footage because of this.

Price

Pricewise, two-piece toilets are the clear winner.

One-piece toilets usually cost much more than two-piece toilets. This is because of the amount of work and resources that goes into producing a seamless design.

Also, since two-piece toilets are still more popular, they have a higher demand. So, they are supported by the economy of scale.

Because one-piece toilets weigh heavier, shipping costs too can be higher. (though shipping cost won’t matter if you order from a place like Amazon where they offer free shipping to members.)

But still, I don’t exactly understand why one-piece toilets have to cost so much. Because apart from how they look, there’s no significant difference between their functionalities. This price difference can be seen even within the same manufacturer and the style.

So, if you’re going for a budget-friendly approach, a two-piece toilet is best for you.

Replacement factor

Replacement factor is another area where two-piece toilets win.

If something goes wrong you can replace the individual parts of a two-piece toilet. But if it is a one-piece toilet, the whole unit (bowl and tank) has to be replaced.

Let’s assume you have an issue with the tank like a crack or damage. Then, only the tank can be replaced while leaving the bowl as it is, and vice versa. Even if something goes wrong, the removable tank can give access to the plumbing inside.

So long term, with a two-piece toilet there is less risk and less cost if anything happens to the tank or bowl.

Weight and Transport

Generally, a two-piece toilet weighs lighter than a one-piece toilet. A one-piece toilet weighs something close to 90 pounds, while a two-piece toilet generally weighs only about 60 pounds.

So one man can lift and move the parts of a two-piece toilet. However, you need at least two people or a hand cart to move a one-piece toilet.

Transporting a two-piece toilet is also easier. That’s because two smaller components can be packaged and handled with ease. But the heavy, unwieldy one-piece toilets is harder to handle and requires a larger box and more storage space.

Ease of Installation

Considering installations, both one-piece toilets and two-piece toilets have their own advantages.

It is easier to install the one-piece toilet once we have it in the right position. There is no second tank installation process. But moving and maneuvering it into position requires extra helping hands.

If you’re planning on installing the toilet by yourself, a two-piece toilet is the better option. This is because it’s easier to carry two small and light components, rather than trying to move one heavy and bulky component. But there will be a second assembly process.

You are also likely to crack the porcelain while trying to assemble the tank in a two-piece toilet if you aren’t careful enough. So, the installation of a two-piece toilet is a bit more tricky and time-consuming compared to installing a one-piece toilet.

Performance and Functionality

Performance and functionality are two factors that don’t really depend on the type of toilet. They depend on toilet design, flushing power, and efficiency. I have found in both one-piece and two-piece toilet types, models that flush well and as well as those that don’t.

Both one-piece and two-piece toilets come with same different flushing technologies. (From flapper flushing systems to tower flushing systems). They are even available in low-flow versions, where very little water (as low as one gallon) is used per flush.

Any toilet (either a one-piece or two-piece) can have up-to-date flushing technology. Performance and functionality mainly depend on its year of manufacture.

So flushing performance and functionality is something you need to check with each individual model whether it’s a single piece toilet or double piece toilet.

Customizability

This is yet another factor that’s common to both the one-piece toilet and two-piece toilet.

Regardless of the type, a wide range of toilets with specific features and customizations is available to satisfy a broader range of customer requirements. They can have varying colors, bowl sizes and shapes, heights, trap ways, high-tech flushing systems, waterless flushing mechanisms, slow closing toilet seats, etc.

So, you can get all the specifications you wish for your toilet, regardless of its type.

My Conclusion and How to Pick

Now that we’ve gone through almost every aspect you need to consider when buying a toilet, here’s the bottom line.

There’s no unifying way of saying one is better than the other. In the end, it all comes down to your available budget, personal preference, and individual requirements.

If what you’re looking for is an attractive, easy to clean and sturdy toilet, investing in a one-piece toilet is hands down, the best option for you.

Related Questions:

Can a two-piece toilet be replaced by a one-piece toilet?

Yes, it can. As long as you stick to the right measurements and rough-in distance (distance from the wall behind the toilet to the center of the outlet pipe), you are good to go.

Do I have to replace a one-piece toilet if the seat breaks?

No. You can replace only the seat since it’s a separate accessory. You only have to replace the whole unit if the ceramic/ porcelain is damaged.

Do I have to replace a one-piece toilet if there’s a leak?

No. Most leaks usually happen because of aging gaskets. It’s easy to replace them. You only have to replace the toilet if the porcelain/ ceramic is broken or cracked. Take extra care not to damage the toilet while replacing the gasket.