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Does a Shower Drain Need a Vent? (Read This First!)

At which point can a person call a plumber? If you thought after flooding the whole house, then you are not wrong but that is also an absurd thing to guess. However, the main thing to take away from here is that at any moment the drainage system of a homestead is bound to fail.  

Sometimes it can happen to poor construction and poor planning, sometimes it can happen to faulty products or damaged connections, and it can even be due to not following simple instructions laid by the architect. 

Regardless of the cause, we understand that a drainage system plays an important role in constructing a homestead. In this case, does a shower drain need a vent? That is exactly what we are here today to answer. 

What is a shower drain vent? 

The shower drain is the drain that is joined with the plumbing fixture. It will carry the water and funnels into the sewage wastewater system when we shower or use the bathroom. The process is quite simple as to how it works. 

However, the shower drain is not optimally functional without the vent placed inside the plumbing fixture. The shower drain vent is something that will evaporate the wastewater in the pipes that are usually blocked in the washroom. 

Does a shower drain need a vent? 

A shower drain does need a vent. That is something vital for the shower drain as well as that it is a required part of any plumbing fixture drain. If there is no vent present in the shower drain, then the shower will not drain efficiently. Vent pipes allow air into the drain system.  

A shower drain vent is a particular system that keeps everything in the bathroom in a particularly good flow. It keeps everything regulated and as well as keeps the drainage system functional. 

If there is no vent in the drain of a shower or any other drainage system for that matter, a multitude of things can go wrong. Some of those things are given below with some brief context. 

Fresh Air:

One of the reasons the shower drain vent is needed is because usually after a bath the residual soapy water will need a place to go. It cannot just go to the same place as all the waters.
Here is where the vent comes in and it plays a crucial role in draining the excess water waste as well as it will help control the air pressure inside the drain. This is because fresh air comes through the air vent and in turn, allows for a proper drainage system. 

Blockade of Water waste:

If there is no vent in the drainage system of a shower drain then the extra water waste will end up overflowing and sometimes get blocked causing an overflow sometimes. This ends up making an often-disgusting mess in the bathroom. 

Foul Smell:

If we do not install a proper vent in a shower drain system, there will come a time when we suddenly hear loud bubbling and gurgling sounds in the bathroom. This is a result of an improper drainage system. 

There is also the other fact of getting a pungent rotten egg smell from the shower drain. 

Will a shower drain without a vent? 

Shower drains are meticulously designed to make sure that there are no sewer gasses that back up in the bathroom that we are going to be residing in. Thus, we can understand the value of a shower drain.  

Now comes the reasoning of why we would need a vent in the shower drain. If we happen to find ourselves in a situation where we do not have the vent in the shower drain, then the shower will not drain in a correct manner

A shower generally has a standard requirement of a 2-inch drain pipe, then the vent pipe should be as much as the drain pipe or half of it depending on the local system. 

What happens if you don’t vent a shower drain? 

The shower drain system is a crucial part of the whole house’s draining system. The shower drain system can function without a vent. The vent is not a necessity but rather a recommendation. 

It is a recommendation because of the multitude of problems you might be facing if you do not have a shower drain vent. Some of those problems that you would face are listed below in brief. 

Sewer Gas:

The shower drain system is designed to keep sewer gasses out and make sure the water drains perfectly. It has a crucial job. However, if there is no vent then there will be sewer gasses coming in through the shower drains.  
This is because the shower drain vent helps the gasses regulate easier as well as maintain a steady flow of water. 

Slow Draining:

As we mentioned above the shower drain vent maintains a steady flow of water through the system. If the fixture is left without a vent, then the water will drain slowly and sometimes not drain at all. 

Gurgling Noise:

Sometimes we can see from horror movies that the drainage systems of the shower, tub, or sink make terrifying noises and ultimately scare the inhabitants of the house. They think it is some kind of paranormal activity. 

However, that happens due to missing vents in the drainage system. 

Where is the shower drain vent located? 

The shower drain is a crucial part of building a proper bathroom. This would block any sort of gasses from the sewers from coming into the washroom. However, this will not work properly if there is no vent included in the shower drain. 

Now if someone were to locate the shower drain vent in their homes, to check if it is installed or not. One would need to go to the roof of the house and check the roof line for the plumbing vent. We would need to find it for making repairs or even inspect it to make it work better. 

Regardless of the reason, the shower drain vent should look like a vertical pipe that would run through the roof. It is compatible and works alongside the drainage pipes so it will not be too hard to identify. 

What are the shower drain vent requirements? 

The vent system is an essential element for the construction of a proper household. This is entitled to the fact that we need convenience and the vent in every drainage system provides that particular convenience and many more things. 

Therefore, understanding the requirements for the venting of drainage systems in the house as well as for the main shower drain is discussed below. 

Needs to Stay Dry:

When installing the vent pipes, they are supposed to be installed in such a way that they will stay dry. This is a requirement that we cannot ignore while setting up the vent for the shower drain.  
So, in order for the pipe to stay dry, we need to emerge from the top of the drainpipe. That needs to be vertically at or no less than 45° from horizontal. This way water will not back up into the pipes. 


When we make the connection between the drain and the horizontal drain as well as the vent pipe. The vertical pipe of a combination drains and the vent system creates the difference between the fixture drain as well as the horizontal drain. 

This is where 8 feet needs to be the maximum vertical distance.   


Shower draining pipes require the size to be a 2-inch drain pipe. Therefore, the vent pipe cannot be more than 2 inches and thus has to be either 1 ½ inches or 2 inches. 

Does a bathtub need a vent? 

A bathtub also needs a vent. Normally we understand the need for a good drainage system in the house. That is also conjoined with the need of having a proper shower drain vent. Otherwise, the equipment would not properly prohibit the sewer gasses from coming in. 

Since we need something like this in our bathroom for the shower drain. It should be a given that anything in the bathroom, be it a sink, toilet, floor drain, or bathtub, we would still need a plumbing vent on the drain. 

That will enable it to work efficiently or there might be sewer gasses coming in. 

Final thoughts 

A crucial part of the house is the drainage and they need to be perfectly maintained at all times for everything to function properly. This is not the case when there is no vent in a drainage system, it can be anything for the shower or the sink in the dining. They all need a vent to work properly.