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3 Signs You Have A Clogged Plumbing Vent And What You Need To Fix

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Plumbing is very important in any house. It keeps things running smoothly and hygienically, and in modern times we wouldn’t be able to cope without it.

When things go wrong with your plumbing it can be stressful and disruptive. 

If your plumbing vent becomes clogged then it could stop your whole plumbing system from working.

But how can you tell if your plumbing vent is clogged? And once you have figured out the problem, how can you fix it?

We have put together this useful guide to help you figure out whether you have a clogged plumbing vent and explain how you can fix the issue. Keep reading to find out more. 

What Is A Plumbing Vent?

Despite the importance of plumbing systems, not many people are aware of the different parts of their own plumbing system and how it plays a part in the daily running of their home. 

The drainpipes are a significant part of the plumbing system that can become clogged, and they deal with water and liquids.

The plumbing vent is different in that it is used to remove gas from your home and to prevent odors from building up by supplying the plumbing fixtures with fresh air.

The other important role that plumbing vents play is to ensure that the air pressure in the plumbing system is properly regulated. 

The plumbing vent pipe is usually found in the roof. It is attached to the drain line and runs vertically.

The vent stack that connects to the roof vent is essential for maintaining the right pressure in the system.

You will never find a plumbing vent (see also ‘What Is A Plumbing Vent And Why Is It Important In A Plumbing System?‘) close to a window or a HVAC, as the fumes need to disperse without contaminating the air that comes into the house. 

How Can You Tell If The Plumbing Vent Is Clogged?

As you can see, the plumbing vent is very essential to the plumbing system in your house.

If it gets clogged you need to know as soon as possible so that it can be fixed. But how can you tell if it is clogged?

The Smell Of Sewage

If you notice strong smells of sewage in your house then it is likely that the vent pipe for your toilet is clogged.

One of the important jobs of the plumbing vent is to remove unpleasant odors, so if they are permeating through your home then the vent isn’t working. 

If the vent is clogged then the sewer gasses will not be able to escape. The smell could also be coming from your sink.

It is very unpleasant, but it is also unhygienic to breathe in the methane gasses. You might need to call a plumber as soon as possible to get the issue resolved. 

The Sound Of Gurgling

Another indication that the plumbing vent is clogged is a gurgling noise. After you flush the toilet, the drains might make a gurgling noise.

These sounds can also come from the sink. But why does it happen?

If the plumbing vent is clogged then the air won’t be able to escape through the plumbing system.

It will try to find another place to escape from which is often your sink or toilet. As the air tries to get out, it causes a gurgling noise. 

If you hear gurgling noises coming from your toilet, sink or other drains in the house then you might need to get a plumber to come and inspect your plumbing system. 

The Speed Of The Drains

If your drains are running slowly then there are lots of possible reasons for this, but one of them is a clogged plumbing vent.

The plumbing vent is important for maintaining the correct air pressure in the plumbing system.

If the vent is broken and the pressure is off, this could cause the drains to run slowly.  

How Can You Clear A Clogged Plumbing Vent?

How Can You Clear A Clogged Plumbing Vent?

There are two ways to clear a clogged plumbing vent – one method involves getting on the roof to clear it from the outside and the other method involves clearing it from the inside.

Let’s take a look at the two different methods. 

Method One – Clean From The Outside

The first method is quite tricky as you have to climb up onto the roof. You should only do this if you can do it safely, and you feel confident. 

Once you are on the roof, and you have located the plumbing vent, you will need to get someone inside the house to flush the toilet.

Put your hand over the vent- if you cannot feel any suction then the blockage is down inside the vent. 

The best way to remove the blockage is with a plumber’s snake. You can also use a hose from your garden to help flush out the debris.

Once you have done this, the toilet should be flushed again so you can check for suction. If you can feel suction then you have fixed the problem. 

Method Two – Clean From The Inside

If you don’t feel comfortable climbing on the roof then you can also clear the clogged vent from the inside.

This only works if you have a PVC pipe, not an iron one. You should be able to tell easily, as a PVC pipe will be white. 

In the attic, locate the area where the plumbing vent comes in from the roof and follow it to an area where it is above the kitchen or the bathroom.

Using a hacksaw, carefully remove a section of the pipe. It doesn’t need to be a big section, only large enough to fit a plumbing snake down. 

Push the plumbing snake down the pipe until you find the clogged section.

If you cannot find it, remove the plumbing snake (see also ‘Best Plumbing Snake For Your Bathroom‘) and push it up the other side of the pipe that is coming from the roof. 

Once the blockage has been removed you can fix the pipe with cement, and either PVC couplings or rubber couplings.

You need to make sure you do a good job of fixing the pipe, or you could end up causing a different set of issues. 

When Should You Call A Professional?

There are some occasions when it might be better to call a professional plumber to help you fix the problems with your clogged plumbing vent: 

  • If you do not feel comfortable attempting the above methods to remove the blockage 
  • If you try the above methods, and they don’t work
  • If you are concerned about a strong smell of methane or sewage smells in the house which could be harmful to breathe in 

Whilst fixing the issue yourself could save you some money, it is always better to be safe than sorry.

Plumbing issues can be complicated, and it is not always something you will be able to fix yourself. 

A professional plumber will be able to carry out a full inspection of your plumbing system to quickly identify any issues, giving an accurate diagnosis of the problem. 


The plumbing vent is a very important part of the plumbing system in your home.

It allows harmful and unpleasant gasses to be removed, it provides plumbing fixtures with fresh air, and it helps to maintain the correct pressure in the plumbing system to keep everything working smoothly.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases. When it comes to dealing with clogged drains, many homeowners turn