How a Bathtub Works? Plumber Explain

Every household has at least one bathtub. Although many people use them every day, do we actually know how they work? A bathtub, also known as a tub is a container that is filled with water, and it is used to take a bath. A good start is to understand which materials are used to build a bathtub and how it works. So, let’s get started!

So, How a bathtub Works? Each bathtub consists of two main parts, the water supply, and the drain. For water to flow into the bathtub, two water supply lines (hot and cold) are connected to the faucet from which water enters the tub. The drain is placed at the bottom and serves to drain the water to the home’s drain line.

As we already mentioned, each bathtub consists of two water supply lines (one for hot and one for cold water) which are an integral part. It should be noted that when water enters the bath, it can be through the faucet or through the showerhead. In the next chapter, we’ll get a little bit deeper into the working principle of a bathtub plumbing system and how it works.

Basic Parts of a Bathtub

To understand the working principle of a bathtub, here are the main parts that you must know:

  • Hot-water supply pipe
  • Cold-water supply pipe
  • Drain
  • Overflow pipe
  • Rim
  • Tub faucet
  • Flexible connector
  • Waste outlet

Now that you’re familiar with the basics, it’s time to go a little deeper into the story.

How Bathtub Plumbing Actually Works?

As we have already mentioned, each bathtub consists of two main features: the water supply and the drain. Now we’ll explain this plumbing system in a little more detail.

In order for the water to flow into the bathtub, there are two water supply lines: one for cold water, which is coming directly from the main water supply, and one for hot water, which is coming from the water heater. These are pipes laid out just under the bathtub, which are usually made out of red and blue PEX tubing, copper, or cream-colored plastic CPVC. Both of these supply lines have their own shutoff valve in case of an emergency.

The water can flow through the faucet into the bath or through the showerhead. By using handles, you control the temperature of the water. Since both the hot and the cold water arrive from the faucet, by turning one of the handles you open a valve that lets a certain type of water flow.

Furthermore, with the help of basic physics, the excess water after the shower or bath flows towards the main drain line, which is placed under the floor through the tub drain and through a P trap.

The Plumbing Diagram Of the Bathroom

A Basic Plumbing diagram of the bathroom

An average bathroom usually has three main parts, which are connected to the main water supply, and those are: the bathtub, the sink, and the toilet. The first two are connected to the water heater to provide both cold and hot water, whereas the toilet doesn’t require this function since it uses only cold water. Each of these three plumbing fixtures has its own drain, which is connected to the house’s drainage system.

The drainage system works by releasing the wastewater to the main sewer line. In order for the water to flow down into the sewer, suction is needed, and this is solved by attaching another pipe to the main drain pipe, which runs towards the roof of the house, along the wall. This pipe is called a vent stack.

Do All Bathtubs Work Same?

All bathtubs are designed to operate on the same working principle, where they are connected to the main water supply lines and a drain system. However, there are different types of drain systems (6 common types) when it comes to bathtubs, but overall, their role is the same.

There are also various models of bathtubs (whirlpool and air tubs) that have a built-in pump, which is used to create an allover bubbling massage. These bathtub models use small pumps that need electricity to operate.

What if My Bathtub Doesn’t Work?

If you find yourself in a situation where your bathtub isn’t working, and you don’t know what the problem is, then it’s recommended to seek professional help. Most people don’t have experience in this field, so to avoid doing even more damage, contact a professional plumber for help. Whether it’s the bathtub drain, a water leak from your tub, or a water supply issue, diagnosing the problem will help both you and your chosen plumber.

The Most Common Bathtub Problems

Most common problems that you might have with bathtub

Below we have listed some of the most common issues you will most likely face if your bathtub is not working properly.

  • Tub Faucet Leak

This is a very serious problem if it is not resolved in time. You can easily face a large water bill at the end of the month. However, in most cases, this problem can be easily solved and you don’t need to panic. The hardest part is to find the leak (where it is coming from) because there are a lot of different pipes in the bathroom plumbing system.

  • Low Water Pressure

This issue can be caused by one of two factors: the pipes through which the water flows towards the showerhead or the showerhead itself. To figure out the main cause of the problem, you can let cold water flow out of the showerhead, and depending on the pressure increase, you can figure out where the problem lies.

  • Slow Draining

Another problem that you can face with your bathtub is connected to clogged pipes. However, this issue you can solve on your own with the help of different cleaning fluids and chemicals. This issue is usually connected to debris such as hair getting stuck in the drain pipes, which causes the pipe to clog.

  • Cracks in the Bathtub

After many years of use, some bathtubs may have cracks that can lead to leaking. However, these cracks can be so small that you can hardly even notice them. To detect them, you need to inspect each part of your bathtub.

How Does a Bathtub Drain Work?

A bathtub drain is usually located at the bottom of the tub and can be placed in the middle or at one end. Their main function is to let water out of the tub. Most bathtubs come in combination with two drains. They are connected through the siphon, and they provide the connection between the latter and the bathtub.

Bathtub drain system

In order to turn your bathtub into a proper bath rather than just a shower, a plug is required which is placed in the drain hole. Depending on your taste, there are a few possible choices when it comes to drain plugs such as a plug connected to a cable, a pop-up system, or a stopper.

However, two different drain systems are most commonly used in a bathtub: pop-up and plunger-type.

By pushing the pop-up, it will go up or down. If the pop-up is in the up position, the water will go through the drain. The plunger-type is simpler since it is connected to a cord, and if you want to stop the water from flowing, you simply place the plunger into the drain hole.

If you have a hole in your bathtub, be sure to read this article: How To Fix a Hole In a Bathtub?

How Does a Bathtub Overflow Drain Work?

The overflow drain is a safety measure that is usually installed near the edge of the bathtub and its main purpose is to stop the water from overflowing. The overflow drain is connected by a flexible pipe and is usually, more or less, hidden or at least fairly invisible.

Bathtub overflow drain working principle

There are two options when it comes to an overflow drain: an anti-overflow safety device or an overflow system. The first option is usually installed in a way that water can be freely drained, in other words without letting the plug close. The second option works by using physics and letting the water fall through the overflow drain. Another important detail to know is that freestanding bathtubs usually don’t come with an overflow drain due to aesthetic reasons.

How Bathtubs Are Made?

Bathtubs come in all shapes and sizes so the most important thing is to choose one which best suits your needs and can fit in your bathroom. Some of the most common shapes of bathtubs are square, oval, rectangular, round, or even asymmetrical. Furthermore, some of the most common types of bathtubs are whirlpool bathtubs, built-in bathtubs, free-standing ones, and shower baths. When it comes to material, these are the most common ones:

  • Cast Iron

This type of bathtub is rarely used nowadays due to its heavy weight. This means that it can only be installed in places where the ground can support the weight of the tub. On the other hand, it does have some great traits. It is very easy to uphold and will keep your water hot for a longer period due to the insulative properties of iron.

  • Enamelled Steel

The biggest and probably only downside, when compared to a cast iron bathtub, is its inability to keep water hot for as long as a cast iron tub can. Other than that, it is a much better option considering its durability, cheap price, and easy maintenance.

  • Acrylic

Acrylic is a material that is most commonly used in a bathtub. Its lightweight, cheap and it comes in all sizes and shapes. This material also perfectly retains the heat, and that is why its popular. The only downside is that it is very sensitive to scratches and rough and sharp objects should be avoided.

FAQ: People Also Ask

Should you plunge into a bathtub?

Since it is a very easy solution for a problem that might cause further issues, the answer is yes. You can use a cup-style plunger, the one most often used, to avoid being knees deep in dirty water due to a clogged drain.

Can you use a toilet auger in a bathtub?

A toilet auger is only necessary if you don’t have a bathtub or sink clog. The auger was made to help you solve the toughest of clogs. An even more advanced option is a drain snake but only use this in extreme cases.

Final Thoughts

Bathtubs come in all shapes and sizes and finding one which suits you best is most important. Most of these bathtubs, no matter how different they are work by being connected to a water supply and the main drain lines. In this article, we’ve also talked about some of the most common issues when it comes to bathtubs in order to help you decide whether you require the help of a plumber or not. Either way, now you know how a standard bathtub works!

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