Why do you need the side hole of the toilet tank: answer from a plumber
Not everyone knows why the side opening of the tank is needed. This design element is not available on every model. There are several myths surrounding the purpose of this hole that are not true. I will tell you why this window was added to the design, I will analyze incorrect hypotheses about its purpose and I will explain how it should be used and how it should not be used.
Purpose of the hole: the plumber's answer
My little nephew asked me about an additional hole in the tank. I used to connect the toilet several times with my own hands, but I couldn’t immediately answer why they made this window. The question was all the more complicated because some models of tanks have it, and some do not.
First I tried several versions:
- The window prevents the tank from overfilling.
- Air enters through the hole on the side, equalizing the pressure when the water is drained.
- This is a purely decorative element that is needed to install a beautiful plug.
However, these versions did not seem convincing to either me or my nephew. Indeed, it is unwise to make a decoration on the side, where few people will see it. The version that the window plays the role of protection against overflow also does not stand up to criticism: after all, water will pour out of it onto the floor, just as it would pour over the edge of the tank.
The second version seemed somewhat more convincing.Indeed, when draining a large volume of water, the pressure in the tank should drop sharply, which will prevent the water from coming out. Air from the room will be sucked into the side window, which will compensate for the pressure drop and drain the water without interference. However, upon closer examination, this version also disappeared: after all, tanks without a hole work no worse than models that are equipped with one.
In search of an answer, I turned to a forum of plumbing professionals. The answer turned out to be simple and clear: two holes made on the left and right allow you to connect the tank to the water supply in cramped toilet rooms. If the hole were made only on one side, there would be a risk that it would not be possible to make a water supply from the pipe located on the other side of the tank.
After connecting the liner into one hole, the second remains unoccupied. It is closed with a decorative plug or left open. That's the whole secret!
Which tanks have an additional side window?
The answer I received turned out to be simple and understandable; it completely satisfied my nephew, and it seemed comprehensive to me. To finally close this question for myself, I studied several more publications and pages of specialized forums.
First of all, acquaintance with the variety of models of modern toilets showed that not all models of compact tanks actually have an additional window. Its presence depends on the type of water supply:
- The traditional type involves supplying water from the side. This design was first developed in separate toilets, in which the flush container was located on the wall, above the seat. With a lateral connection, it is important which side the water supply pipe is located on.
- A more modern design involves introducing water from the bottom of the tank. In this case, there is no need to make symmetrical windows for water supply: the distance between them is small, and even if the hole is located on the opposite side of the pipe, the hose can easily reach it.
Thus, an additional side hole is an attribute of models in which water is introduced from the side.
How to avoid flooding your neighbors: adjusting the fittings correctly
The hole in the tank looks like a dangerous design element: if the water level rises higher, the excess will spill onto the floor. In such an accident, you can even flood your neighbors. However, after studying the design of the fittings in my tank, I realized that such an outcome was unlikely.
There are two mechanisms that protect against flooding:
- A faucet with a float through which water enters the tank. When the level rises too high, the lightweight plastic cup will float up and pull the rod it is attached to. The other end of the rod will act on the faucet and turn off the water.
- Overflow pipe. Its height is adjusted so that the upper edge is below the hole, but above the water level at which the float cuts it off. If the float valve fails and water continues to flow into the tank, its surface will rise above the neck of the overflow pipe. After this, all excess water will go into the drain of the tank and will be drained into the sewer, and not onto the floor.
To make sure water does not overflow from the toilet tank, place dry newspaper underneath it. Every drop will be visible on the paper. Even if drops rarely fall, the leak can be noticed by the deformation of the wet and then dried paper.
If you find that water is leaking from under the secondary window plug, check to see if the float valve is working. This is easy to do: remove the reservoir cap and lower the float by hand. Water should come out of the tap. Then lift the float and make sure the water stops flowing.
You can adjust the position of the float by shortening or lengthening the rod on which it is attached. For example, I decided to shorten it a little to ensure that water does not leak. For this purpose, plastic structures have toothed strips with clamps. It is enough to slightly bend the metal wire.
Is it possible to connect a washing machine drain to a side window?
Another interesting idea that I came across on the forum while I was looking for an answer to my nephew’s question was connecting the washing machine drain to an additional window. Technically, this is easy to do: we insert the hose into the tank and secure it with a rubber seal or sealant. The idea promises two benefits:
- Saving water. This effect is achieved due to the ability to reuse the machine drain to flush the toilet.
- Simple and clean wastewater disposal. When connected to the tank, the hose is secured and there is no risk of it popping out.
However, upon closer inspection, this tempting idea has several drawbacks. First of all, when the machine drains the water, the tank will already be full. This means that the drains will create an excess volume, which will either go into the overflow pipe or even spill out through the top onto the floor. Of course, you can drain the tank before washing and shut off the flow of water from the water supply, but this complicates the scheme.
In addition, the waste water from the machine will contain powder residues, dirt, possibly thread particles and other debris.All these contaminants can clog the drain fittings, which will lead to incorrect operation. Therefore, in my opinion, it is better to abandon the implementation of this idea.
This is how searching for an answer to my nephew’s question helped me better understand the principle of operation of the cistern and take a fresh look at the usual plumbing device. I hope that you find this material interesting too!
Author: Yuri Mikhailovich
Incredible! These holes allow you to choose whether to install a faucet with a float on the right or left, depending on which side is more convenient! And millions of people had no idea! But in general, looking at the installed tank and noticing the complete symmetry of the holes, only a moron could not guess.
I wonder if I’m the only one so “smart” that I’ve known this since childhood because my father told me this, who was told this by my grandfather as a child...
By the way, the cast iron tanks also had 2 recesses for the valve
I'm shocked, toilet paper was invented (maybe some people don't know)
I don’t need a monument during my lifetime. just say thank you
I didn’t know what it was intended for and I fitted a drain outlet from the washing machine into this hole
The plumbers will anathema you!!! I adapted the drain from the washing machine!!! )))) Well done!!! Saving water)))
In addition to connecting water, a flush handle with side fittings was installed in one of the holes.
author, I’ll suggest a topic - why is there an elevator in the house?
I wonder what the vents on the windows are for.
In short, Kulibins, water was connected into one hole, and the drain mechanism into the second, it used to be on the side. Only then did the upper lever (button) for draining appear.
you can also charge flavor tablets through it
What killed me was the beginning, “I installed toilets myself many times,” how can you do something without knowing the subject?
What killed me more was the title of the article and further in the text: “In search of an answer, I turned to the forum of plumbing professionals.” This is from the section: “I advise everyone to do this, I don’t know why, but my mother does it.”
There needs to be such a discussion about the extra hole in the tank! What if my nephew asks where children come from? You see, dear nephew, women have an extra hole...
You can also go there +18
Amazing discovery! Remarkable intelligence and power of engineering.
On the plumbers website, of course.
And the author had to make a written request to the manufacturer.
Otherwise they will make holes, but why is a secret. Inhumans.
And the article and the comments are some kind of sketch... you’re burning it, of course
The author had fun!
I have installed toilets many times before, but never thought about why a cistern is needed. It takes up space that is not enough in the toilet, but does not provide any benefit. But I began to study this issue and realized that the tank was needed to put a roll of toilet paper and an air freshener on it. You can also put a book/magazine on it to read in the toilet. It turns out to be a convenient thing. But that’s not all, because for some reason some people connect it to some pipes. I began to study why they do this and realized that the drain from the washing machine could be brought out there through a hole on the side. I plan to find out why the toilet itself is needed, otherwise it’s inconvenient to wash in it, there’s not enough space and you constantly slide into the drain
The author tell us also what the hole in the ass is for. Otherwise no one knows, everyone is guessing...
Laughed heartily.
Give the dude a Nobilevka. Otherwise, the whole world lived and factories riveted two holes per tank for the valve and did not know why.
Now I know exactly what to advise gloomy plumbers instead of a circus
Thank you for an excellent, and most importantly funny article!