a year ago
The bathroom is a highlight for home renovation. A toilet is a must for the bathroom and is particularly important. How to choose an ideal toilet amongst various options in the market? We will give a tutorial today.

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Usually, a homeowner may purchase a toilet only base on its look and glaze, but some more advanced buyers care about how it flushes. The insiders know that the soul of a toilet is not its appearance, but the invisible parts, the design of the curvature of the trap way. A good trap way can save water and flush smoothly, rarely clog or splash water. When you buy a toilet, please pay attention to whether it would clog, splash water, flush well, save water, and soundproof. There are two flushing methods of the toilets on the market:

Wash Off

Wash off, as known as flush down and wash down. It is the regular European toilet design. The characteristic of this kind of toilet is that the tank is relatively small and narrow, the defecation opening (the big hole inside the toilet) is large, and the slope design inside the toilet is steep (there are jokes about how the water splashes when you take number two). It uses the pressure of toilet water to wash away the waste, so it makes a loud noise with tiny splashes. It contains about 6 liters water (1.6 gallons), and it is relatively water saving.

The wash-down toilet started in Europe. Later, the two major Japanese companies TOTO and INA produced this type of toilet. Although it is loud, and sometimes scary at night, the tank is relatively small, so is the toilet itself, which takes very little space. The trap way looks like a “ㄣ” with minor curvature. The chance of clogging is small because of the large aperture of the defecation opening.


Siphonic. It is the most common type of toilet of Northern American, Taiwanese, and Japanese brands. Its water tank is bigger and wider, so is the toilet bowl itself. The slope is long and inclined, with a small and round defecation opening. The trap way design is a curvy “S” which makes the toilet big. The bottom of the toilet has many curved lines that are invisible from outside.

When a siphonic toilet flushes, a little bit water first accumulated in the toilet, which may make some people think the toilet is clogged, then the pipe turns into a vacuum and creates a siphon sucking the waste and water down. It does not make noise while flushing, but you can hear a puff sound when the siphon finishes meaning the air pumps back to the trap way. The siphon occurs when the water accumulates to a level that is enough to fill the entire trap way, so the water must reach 3.5 gallons (12 liters). To make it more environmental-friendly, the manufacturers adjusted the water to 1.6 gallons, which is a major improvement for siphonic toilets. Water volume directly determines the effect of siphon.

Another type is spray siphonic toilet. It has the advantages of both washdown and siphonic toilets and is currently the most popular type. It flushes at the lower opening, with strong siphonic power and almost no sound.

Key Points

If it flushes smoothly

The trap way area determines whether it can be clogged easily. The washdown toilet design does not include backwater bends. It flushes down, compared with the siphonic toilet, which is not easy to be clogged. The diameter of the siphonic toilet trap way is only about 22 inches, and the flushing water volume is only about one third compared with the washdown toilet, which makes it easier to be clogged. People joked that people who have a siphonic toilet at home must have two essentials, a wastebasket, and a plunger. Because the paper must be thrown into a basket, or they may clog the toilet that will require a plunger to unclog it later. Pay attention if the toilet is glazed, which determines if it is easier to get dirty or clogged. TOTO toilets are not clogged, but the surface is very smooth.

If it splashes water

No one wants to be splashed when they are using the toilet, which is unpleasant and bad for hygiene. There are various reasons cause splashing, such as toilet structure, falling height, falling angle, and the user’s physical condition. Among them, the main factor is the falling height, the higher it is, the greater speed the waste falls into the water, the bigger the momentum, and cause a serious splash. According to the experiment result, when the falling height is more than 8 inches, the splashing is the most serious; when it is less than 5.5 inches, there is almost no splash; and the critical height is 6.5 inches. The falling height is the height difference between the toilet seat and the water seal. The height of the toilet seat is designed according to ergonomics, which is usually the length of an average person’s calf. Thus, the water seal height is directly related to the splashing issue and determines how effective it can prevent smell. Install the toilet into a working position, fill in water slowly until there is water flowing out from the outlet, use a tape measure to get the water seal height. If you wish to get a toilet without splashing, choose a product that the water seal height is about 21 inches.

If it flushes clean

Some European brands adopt the washdown flushing method, using standard UK design. It has a short trap way, a bigger opening diameter, flushes easily using the gravity of water. But the trap way of a siphonic toilet is thin and long because a small diameter can make a better siphonic effect and a bigger flushing force. Inevitably, the amount of water required would increase too. Siphonic toilet users find that it flushes clean when the water is released to a certain height because the structure determines that it needs a lot of water. It is easier for a siphonic toilet to flush the dirt on the surface of the toilet, while the washdown toilet flushes bigger objects better. Each has pros and cons to take into consideration.

If it saves water

Saving water is not only environmental-friendly but also saves money on your water bill. The current standard flushing speed is 1.6 gallons per flush (GPF), which is less than half of what the old toilets use. Thanks to the improvement of hydraulic design, these toilets work just like others. In some cases, they even perform better than the old schooled toilet in cleaning and anti-clogging. So, it is essential to choose a water-saving toilet.

Shopping Guide

  • Outlet. To get the right toilet, check if the outlet is a floor outlet or a back outlet, the installer would not be able to install it without a properly reserved pipe.
  • Measure the distance between the outlet and the wall to determine if the toilet can fit.
  • When you purchase a toilet, you want to observe if the glaze is even. If there are any color differences, deformation, how glossy it is, any defects on the surface (spots, cracks, orange glaze, ripple, uneven colors, or dirt), and whether it can be removed. A high-quality toilet is well glazed, delicate, without any defects, and turns into new every time it is flushed. But if the glazed is in poor quality, the dirt can stick on the surface easily.
  • There are two types of toilets, one-piece, and two-piece. The two-piece toilet is small and suitable for small bathrooms. One-piece toilets have smooth lines and newer design can provide you with more options.
  • Check the internal trap way connection. If the gasket is low-quality, then the toilet is easy to be clogged and leaking. The gasket should be made of rubber or foamed plastic, elastic, with excellent sealing performance.


The flushing method is important. We recommend siphonic toilet because it is quiet, easy to be flushed, and is more aesthetically pleasing-looking into the toilet bowl.

Choose a toilet with a proper water seal height. If it is too high, the water may splash, but if it is too low, the toilet might smell bad.

Pay attention to the glaze. A good-quality well-glazed toilet should be smooth without any blistering and saturated in color. After checking the glaze of the toilet, touch the drain, if it feels rough, the dirt may stick on the surface. A good glaze can make the future cleaning easier, the glaze of a few-hundred-dollar cheap alternative turns yellow fast, and it will be hard to clean once the color turns. The high-quality toilets are expensive because their glaze is delicate and anti-wear. Unlike the low-end alternatives, the high-end toilets were processed at a high temperature and meet the requirement of full porcelain and weigh heavier.