One-Piece Vs Two-Piece Toilets – Pros, Cons & Buyer Guide

Last Updated on July 27, 2023 by toilethaven

Toilets are manufactured as either one-piece or two-piece. But what is the difference between one-piece toilets and two-piece toilets, and what are their advantages and disadvantages?

A one-piece toilet is a toilet whereby the bowl and the tank are manufactured as one inseparable piece, while a two-piece toilet is a toilet where the tank and the bowl are manufactured as 2 separate pieces and are only joined together during installation.


One-piece toilets are heavier and harder to install on your own but are easier to clean and have a seamless and great design. On the other hand, two-piece toilets are hard to clean but easy to install, and you can choose to only replace the bowl or the tank instead of the whole unit, unlike one-piece toilets.

The main disadvantage of the one-piece toilet is that they are heavy, which makes installation a 2-person job. Also, the toilet is shipped in one big odd-shaped box, and as a result, one-piece toilets tend to break during shipping more than two-piece toilets, which are shipped in 2 small separate boxes.

The main advantage of one-piece toilets is that there is a gap between the tank and the bowl. This makes it very easy to clean the toilet since there is nowhere for dirt to hide. Also, unlike two-piece toilets, one-piece toilets will never leak between the tank and the bowl.

So, Can you replace a two-piece toilet with a one-piece toilet?

Yes! A two-piece toilet can be replaced with a one-piece toilet and vice versa. You will only need to make sure that you have checked the toilet dimensions and especially the rough-in, to ensure that the toilet will fit in the space you have in your bathroom.

One-Piece Vs. Two-Piece Toilets Comparison Table

1-Piece Toilets 2-Piece Toilets
Compact Cheaper
Seamless beautiful design Separate bowl/tank replacement
Fast installation One-person installation
Easy to Clean
Fewer leaks
Expensive Needs a bigger space
Heavy Takes long to install
Pricey replacement Hard to clean
Shipping breakages are high More repair/leaks

Some one-piece toilets do not have a water tank (tankless toilets). The bowl receives water at very high pressure straight from the pipes, which is sufficient to flush the toilet. Read more on tankless toilets here.

Some two-piece toilets have their tanks connected directly to the bowl using bolts, while others have the tanks high up the wall, with a pipe joining the tank and the bowl.

One type of two-piece toilet that can easily be confused with a one-piece toilet is the wall-hung toilet. Wall-mounted toilets, as they are also known as have their bowls mounted on the bathroom wall while the tank is concealed inside the wall. Read more on wall-hung toilets here.

Which is Better, One-Piece or Two-Piece Toilets?

So, between a 1-piece toilet and a 2-piece toilet, which is better? Are one-piece toilets better than two-piece toilets, or should you go with a two-piece toilet?

The truth is that both one-piece and two-piece toilets have their own advantages and disadvantages, as I am going to outline. It is, therefore, important that you take your time to examine the merits of each type of toilet before deciding on a final decision.

Let us then look at the pros and cons of 1-piece and two-piece toilets briefly, and then we will discuss them in detail.

Pros and Cons of One-Piece Toilets

The Pros

  • Takes less space
  • Visually appealing
  • Fast to install
  • Easy to maintain (fewer leaks)
  • Easy to clean

The Cons

  • Expensive
  • If one piece (bowl or tank) is broken, you must replace the entire unit.
  • Heavy. Needs an extra pair of hands during installation.

Pros and Cons of Two-Piece Toilets


The Pros

  • Less expensive
  • Either bowl or tank can be replaced separately
  • One-person installation job

The Cons

  • Takes more space
  • It takes time to install
  • Harder to clean
  • More repair jobs

One-Piece vs. Two-Piece Toilets Compared

Let us now dive deeper into the 1-piece vs. 2-piece toilets debate and see why you should buy one type of toilet and not the other.

I should also remind you that there are many other features/factors to consider while buying a toilet, not just based on the number of pieces it has, as illustrated in this post.

1. Size

One-piece toilets are more compact than two-piece toilets. They take up less space in the bathroom compared to two-piece toilets in terms of depth, width, and sometimes even width.

One-piece toilets are shipped in one big box. They are, therefore, quite heavy, especially if you will need to carry it up a series of stairs. They are, however, a great option if you need to install one in a tight space, especially one-piece round toilets.

Two-piece toilets are often shipped in two different boxes. Sometimes the two boxes arrive at different times. Two-piece toilets are less likely to break during transportation than one-piece toilets.

The thing with two-piece toilets is that sometimes one -piece arrives in condition while the other arrives broken. Each toilet type has its shipping challenges.

Modern two-piece toilets are, however, shorter in height compared to the old ones, where the tank could be so high up the wall. Some are almost equal in height to a one-piece toilet. Let’s look at an example.

Toto Ultramax II Elongated toilet

  • One-piece toilet
  • Height: 28.75 inches

Toto Drake elongated bowl and tank toilet

  • Two-piece toilet
  • Height: 28.5 inches

If your bathroom is small, I would advise that you go with a round or compact elongated toilet. Check out the best compact toilets for small bathrooms here.

2. Aesthetics

One-piece toilets are sleeker and aesthetically appealing than two-piece toilets. They come out as more modern and luxurious, while two-piece toilets are viewed as more traditional. Most one-piece toilets are skirted down, concealing the tramway, which makes them look very elegant.

In contrast, some two-piece toilets have many nooks and crannies, especially between the bowl and the tank. Subject to the same light intensity, one-piece toilets glow more than two-piece toilets. This is because light travels in a straight line and bounces off shiny surfaces.

If you are looking for an even sleeker and seamless toilet, I suggest a one-piece dual flush toilet. Dual flush uses flush buttons instead of a trip level. Read more on dual flush toilets here.

3. Cost

One-piece toilets are generally more expensive compared to two-piece toilets with the same features and specifications. This is because one-piece toilets come off as more modern than two-piece toilets.

It is, however, not always the case that one-piece toilets cost more than two-piece toilets. High-end two-piece toilets cost way more than budget one-piece toilets. For instance, the Kohler K-6669-0 Memoirs two-piece elongated toilet costs more than the Woodbridge T-0001 one-piece elongated toilet.

A plumber will charge the same amount of money to install a toilet, be it a one-piece or two-piece toilet.

4. Ease of Cleaning

It is way easier to clean a one-piece toilet compared to a two-piece toilet. Cleaning a skirted one-piece toilet is even better since there are no crevices where dirt can hide; hence the toilet’s surface is smooth all the way down.

Two-piece toilets, on the other hand, are harder to clean than piece toilets because of the gap between the bowl and the tank. It is very easy for dirt to hide there, which becomes difficult to remove.

An exception to this is the Toto Vespin II. Although it is a two-piece toilet, its bowl is skirted down, which, when combined with Toto Cefiontect glaze, makes cleaning it a cinch. It can also be installed in bathrooms with a 10 or 14-inch rough-in.

5. Replacement Cost

If, unfortunately, a one-piece toilet cracks either on the bowl or tank, you will need to replace the entire toilet. This is one of the main disadvantages of one-piece toilets.

If, on the other hand, either the bowl or tank of a two-piece toilet crack, you can always replace the cracked piece only. Just note the model number of the broken piece and order an exact match.

6. Maintenance Costs

Maintenance costs are slightly higher in two-piece toilets than in one-piece toilets. Two-piece toilets have more moving parts than one-piece toilets; hence more replacement parts are needed.

Of importance, in this case, are the toilet tank bolts and washers and the tank-to-bowl gasket. Although these parts are not expensive, once they are one out, you will be dealing with a leaking toilet.

In that case, you will need first to remove your tank, replace the parts, then install the tank again. People who can’t do such repairs on their own will need to pay a plumber instead, which is not cheap.

A leaking toilet is also expensive, more so if you have a wooden floor that can easily rot. One-piece toilets have no tank bolts or gaskets and will, therefore, never have a leak between the tank and the bowl.

Apart from the above, the cost of maintaining a one-piece toilet is not very different from that of a two-piece toilet.

7. Durability

The durability of a toilet, whether a one-piece toilet or a two-piece toilet, depends on the user/owner. If only one or two adults are using either of the two, then they would last for decades. On the other hand, if we are dealing with a house full of kids, don’t be surprised if you are required to replace a toilet seat after two days.

Toilets from reputable brands tend to last longer than toilets from unknown brands, although they tend to be pricier.

8. Water Efficiency

The old models of two-piece toilets have very big toilet tanks compared to the modern one-piece toilets. As a result, modern one-piece toilets are more water-efficient than the old two-piece toilets. The old two-piece toilets use, on average, 3.5 gallons per flush.

Modern two-piece toilets are quiet and fast while refilling the tank after a flush. The old two-piece toilets are noisy and take longer to fill the tank.

Modern two-piece toilets are as water-efficient as modern one-piece toilets. Let’s look at the example below for clarity:

Toto Ultramax II elongated toilet

  • One-piece toilet
  • 1.28 gallons per flush

Kohler K-6669-0 Memoirs elongated toilet

  • Two-piece toilet
  • 1.28 gallons per flush

9. Flushing Power

There is no difference in flushing power between one-piece and two-piece toilets. The flushing power of a toilet depends on so many other factors, which do not depend on whether a toilet is a 1-piece or 2-piece.

I have also written an article on the best flushing toilets in the market. Read it here.

10. Ease of Installation

Installing a one-piece toilet is faster than a two-piece toilet. For a one-piece toilet, you only have to mount it once, while for a two-piece toilet, you will have to install the bowl first and then the tank later.

The only downside to installing a one-piece toilet is that it is heavy; hence you might need an extra pair of hands to help with the lifting. One person can comfortably install a two-piece toilet.

The Best One-Piece Toilets

If you would like to buy a one-piece toilet, the following are the 3 toilets that I would consider as some of the best 1-piece toilets:

1. Toto Ultramax II

TOTO® WASHLET+® UltraMax® II One-Piece...
  • WASHLET+ bidet seat and toilet, specially designed to conceal the WASHLET water supply and power cord.

Toto Ultramax II is a single-flush elongated and one-piece toilet. It is available in white, black, bone, and Sedona Beige.

Ultramax II has a water consumption of 1.28 gallons per flush, utilizing Toto’s tornado flushing system. Its toilet bowl height is 16.125 inches, and it comes with a soft-close toilet seat.

2. Kohler Santa Rosa

Kohler 3810-0 Santa Rosa Comfort Height Elongated...
  • One piece toilets integrate the tank and bowl into a seamless, easy to clean design
  • Compact elongated bowl offers added comfort while occupying the same space as a round front bowl
  • Comfort height: Feature offers chair height seating that makes sitting down and standing up easier for most adults

Kohler Santa Rosa is a single flush elongated and comfort-height one-piece toilet. It is available in many colors, including white, black, and biscuit.

It uses Kohler’s AquaPiston flushing with a flush rate of 1.28 gallons per flush. Its toilet bowl height is 16.5 inches which increases to 17.5 inches after installing a seat.

3. Woodbridge T-0001

zon box=”B07H781NMC”]

Woodbridge T-0001 is a dual flush one-piece toilet with an elongated bowl and comfort height. It is available in white only.

The Woodbridge T-0001 is a sleek and beautiful toilet that also flushes powerfully. It uses either 1 or 1.6 gallons of water per flush. Its seat height is 16.5 inches, and it also comes with a soft closed toilet seat.

Best Two-Piece Toilets

If you would like to buy a two-piece toilet, the following are what I think are the best 2-piece toilets in the market:

1. Toto Drake II

No products found.

Toto Drake II is a single flush comfort height two-piece toilet. It is an improvement of the popular Toto Drake toilet.

Toto Drake II uses the E-Max flushing system, while Toto Drake uses the G-Max flushing system. The difference is in their water consumption. The E-Max flushing system uses 1.28 gallons per flush, while the G-Max flushing system uses 1.6 gallons per flush.

2. American Standard Cadet 3

The American Standard Cadet 3 is a single-flush round two-piece toilet. It has a skirted bowl and a right/comfort height bowl of 16.5 inches. The colors available are white, bone, and linen.

It features American Standard’s EverClean surface and a 3-inch oversized flush valve for a powerful flush. A slow-close toilet seat is also included.


It is safe to say that none between a one-piece toilet and a two-piece toilet is better than the other. It all depends on the preferences of the buyer.

I thought that one-piece toilets would be the end of two-piece toilets, but it looks like two-piece toilets are not going anywhere soon.


1. Can I replace a one-piece toilet with a two-piece toilet?

Yes. The base of a one-piece toilet is the same as that of a two-piece toilet. Just make sure they have the same rough-in. The rough-in is the distance between the center of the drainpipe and the toilet’s rear wall.

2. Which is the best 2-piece dual flush toilet?

The American Standard H2Option Siphonic toilet is one of the best two-piece dual flush toilets.