Why Is The Water Level In American Toilets So High? (3 Reasons Revealed)

Disclaimer: As an Amazon Associate I earn from qualifying purchases.

When we are traveling, we often find something interesting even in the bathroom of other countries. For example, Aussies and Europeans always get surprised about the high water level in American toilets. 

American toilets water level

Why do American toilets have higher water levels? Is it really necessary? I will reveal the 3 hidden reasons in this post. 

Simply put, Americans can benefit a lot from having a high water level in the toilet. This is not just a convention, and the high water level can help reduce odors and prevent smears. 

Why do American toilets have so much water in the bowl?

Different types of toilets have various pros and cons. American toilets have more water in the bowl, but it doesn’t change people’s minds to turn to a European toilet. I summarized 3 main reasons for this phenomenon below.

1. Americans use siphonic toilets

There are two types of toilets in terms of flushing systems: siphonic toilets and washdown toilets. While European countries and Australia are used to washdown toilets, most toilets in America are siphonic.

Siphonic toilets tend to have a higher water level. So, it is not because Americans like to set the water level high, it is due to the different toilet models. 

Siphonic toilets have a “P” or “S” shape of trapway, which is much longer than washdown units. Due to this, it is able to form a siphon and take away the waste. 

American toilet water level

When you flush the toilet, a portion of water will go through the flush ring and come out from the siphon jet. Other water will go to the toilet bowl.

The water that comes from the siphon jet is powerful and will push the water in the trapway to the highest point (also known as the weir) and form a vacuum. In this way, the waste in the toilet bowl will be sucked out.

Compared to siphonic toilets, washdown toilets have a shorter and wider trapway. It takes away the waste by making use of the gravity of water. Accordingly, the weir is lower than one with a siphonic design, making the water level in the bowl is lower.

You can find more information about the difference between siphonic and washdown toilets here. 

So, if you install a siphonic toilet in Europe, the water level will be higher than the ones in your neighbors’ house. 

2. High water level can make the bowl easy to clean

Most Americans don’t like to observe the poop after doing their business. Even though it is an excellent way to monitor our health. They want the waste to disappear as soon as possible. 

When the water level is high, the feces will immerse in the water without sticking to the bowl’s surface. Therefore, it is harder to leave any mark after each flushing. 

When the toilet water level is low, the waste will land on the bowl, increasing the odds of unwanted stains and marks. 

Hence, Americans can save a certain amount of time cleaning the toilet bowl and avoid embarrassment when there is no toilet brush available. 

3. Avoid the awful smell in the bathroom

Different countries have various bathroom cultures. Some countries like to install the toilet in a separate room from showers and sinks, and some countries prefer to place everything in the same room. 

While many people have a bathroom without windows, many people can’t put up with it at all. 

The poops are smelly in any way. When the feces get into the bowl, the odors will start spreading all over the bathroom. If the ventilation condition is not so good, the awful smell will not disappear in a short time which is quite annoying. 

When you use an American toilet, the water in the toilet can become a seal, preventing the smell of poops from coming out. It means that the bathroom will be fresher even if there are no windows or fan ventilation.

Meanwhile, the high water level, along with the long trapway, can also help to prevent sewer gases in the pipe from getting into the bathroom. 

If you know how much effort Americans have put into making their bathroom fresh, you can understand why they insist on using a toilet with a high water level.

Possible issues when using a toilet with a high water level

Even though Americans can get a lot of benefits by using a high water level toilet, they have to deal with some problems simultaneously. 

It is prone to clog

The “P” or “S” shape trapway is a great design for forming a siphonic effect. However, as it is narrower and longer, it is more susceptible to clogging. 

People who use this type of toilet have to prepare a plunger next to it. Luckily, there are a few easy ways for you to dissolve poop stuck in the toilet

It takes more space 

Subjected to the large and long trapway, American toilets will take more space than the European units. It would be a big issue in most cases but could be problematic for those who have a small bathroom. 


People may feel wired when they use the American toilet for the first time because the water level is higher than what they use at home.

I am sure you can continue to do your business without a doubt. There is no significant difference between each other. 

The reason why American toilets have a higher level of water is that they use siphonic toilets instead of washdown ones. 

This type of toilet has a different shape of trapway and uses another way to flush the toilet. As the weir is higher, the water level in the toilet would be higher. 

More water would stop sewer gases from escaping the pipe and reduce odors from feces. Nevertheless, it is apt to clog and takes more space. 

Anyway, you will get used to it no matter whether it is an American toilet or not.

Avatar photo

Kevin Chow is an enthusiast of home improvement. He is an engineer and likes to test all the tech gadgets on the market. He starts to use bidet seats after his journey to Japan and he had tried a few brands.