top of page

Dilemma: One-Piece or Two-Piece Water Closets?

Updated: Jul 20, 2020

With the bathroom as an integral part of everyday life, it is important that we pick the correct water closet (better known as WC or a toilet bowl) for ourselves such that we can go about our business in comfort.

First, let us get into some technical terms that you should be familiar with when picking out a toilet bowl. When it comes to the choosing of designs, it is not purely about the aesthetics but also about the kind of rough-in that design offers.

To make sure you get the right WC, you should check the location of the existing waste pipe and trap distance. Trap distance refers to the shortest-straight line measurement between the finished wall to the centre of the waste discharge outlet. There are two kinds of traps: (1) P-Trap and (2) S-Trap. A P-Trap is when the sewage outlet leads to the wall and a S-Trap is when the sewage outlet leads to the floor.

After you have figured out whether your house needs a P-Trap or S-Trap, you now know the rough-in you need for your new WC. If you are still unsure, do take a picture of the full ceiling of your bathroom and show it to our sales staff for advice.

Next comes the choosing process for the perfect WC and the one thing that pops into everyone’s mind: Should I get a one-piece or two-piece WC? Which is actually better? Is there a difference?

Yes, there is a difference! But it is less so that one is better than the other but more of your own personal preferences. We would be using our own OttO WC models, Mercury and Coral to better illustrate the differences and similarities between one-piece and two-piece toilet bowls.

Here are the factors that might affect your choice:


While doing research online, some might find that it is mentioned that one-piece WCs tend to be smaller in size making them suitable for bathrooms that are smaller. However, this is not always the case. As can be seen from Mercury and Coral, their size differences are not very big, differing at most at 20mm.

As such, sizing should not be the only factor you use to decide between a one-piece and two-piece. Generally, wide varieties of sizes are available for you to choose from so do consult our staff on the sizing you are looking for recommendations to different models.


With regards to cleaning, there is no doubt that a one-piece WC will be easier to clean. As can be seen from the models above, Coral (the two-piece WC) comes in two pieces leaving a slight gap between the water tank and the bowl itself after installation. When it comes to cleaning, this could lead to more work as extra care has to be taken that these areas are kept clean as they are prime breeding grounds for bacteria.

Mercury (the one-piece WC), would not have this problem as it comes in one whole piece. This makes it easier to wipe and wash the toilet bowl. The ease of cleaning should be seen as an important factor especially if you have less time to clean because of a busy schedule.


With regards to durability, if they have been manufactured by the same manufacturer (as is the case for us), they should be similar in terms of their durability.

The inner mechanisms used would also be the same, meaning to say that they should function the same as well. In the case of Mercury and Coral, this stands true as seen with how both utilises a washdown flush mechanism. Therefore, you can be well assured that both one-piece or two-piece WC will be durable for long-term use.


As it is more difficult to manufacture a one-piece WC, prices for one-piece WCs are usually more costly. In the case of Mercury and Coral, Mercury costs about 30% more than Coral clearly indicating their differences in price.

This makes two-piece WCs more affordable and is definitely a considering point if you are on a tight budget.


Some would also find from research online that two-piece WCs are mostly not preferred because of their designs where the comparing point is that one-piece WCs look more modern. However, this is not always the case and is just a generalisation of all two-piece WCs. As we see from Mercury and Coral, the two actually have the same design but it has been catered to meet different needs of the consumers thus being available as one-piece and two-piece models.

While not all our models are available in both one-piece and two-piece options, we make sure that the designs we have are wide enough to cater to the tastes of all our customers. We also ensure that our WCs look modern and sleek, be it one-piece or two-piece.


If you are planning to install the WC yourself, this is an important point to note. As a general guideline, one-piece toilet bowls would be more difficult to install as they come in one-piece and would prove to be bulky and difficult to handle if you are installing it on your own. On the other hand, two-piece toilet bowls will be easier installed on your own as parts are put together separately.

Ultimately, the choosing of a WC is a personal choice and one that you must take serious consideration into as you will be using it every day. For more tips on choosing toilet bowls, check this out!


bottom of page