Symptoms Of A Clogged Drain Vent Pipe That You Never Should Ignore!

The modern plumbing system is highly complex and intricate. It has a major impact on our way of life even though most of us don’t know how deeply.

We began to see its importance when the toilet is overflowing or the drain becomes too slow to dispose of waste. Sadly, most of us don’t act until it’s too late.

But if we carefully observe some symptoms of a clogged drain vent pipe, we can take action before it gets to an embarrassing level and makes our life miserable.

So, I will talk about those symptoms in this article so that you have enough time to take action beforehand. Stay with me!

4 Clogged Drain Vent Pipe Signs

symptoms of a clogged drain vent pipe

Troubleshooting a clogged drain vent pipe is a time-consuming task for any professional plumber. It costs a lot too.

It will charge you higher when you call a plumber after your kitchen sink begins to smell like rotten eggs or the toilet starts to overflow.

So, notice these below-mentioned symptoms before any of these bad things happen:

  1. Sewer Smell

The first telltale sign of a clogged vent pipe is having sewer smell inside your house. When such pipes are clogged, water can’t flow properly through the drain system.

When the toilet vent pipe is clogged, your bathroom will be full of horrible sewer smells. Because when such pipes are obstructed, the p-traps under the toilet or sinks become dry and let the sewer gas accumulate.

So, it’s clear that the drain vent pipe removes the nasty odors and gases. But if the vent pipe is clogged, the sewer gas can’t escape. When they can’t escape, such gases will re-enter your house!

So, there is a high possibility of clogged vent pipe if unpleasant odors keep coming from the sinks or the toilets.

Most people even don’t know that the drain lines need proper ventilation. When vent pipes are blocked, the drain lines don’t get much ventilation and you have a foul smell!

Your drain needs air to equalize the pressure to ensure the free flow of the water. But when the vent pipe is obstructed, it won’t have much air.

  • Slow Drains

When there is a possible blockage in the drain and you have done everything possible to clear that blockage, it becomes another sign of having clogged vent pipes!

But keep in mind that it’s not the only reason why your drains are sluggish. Before you take any actions, you should call a professional plumber to assess the situation and confirm about it.

  • Gurgling Noises

Do you hear any gurgling noises when your toilet, sink, or bathtub is draining? If your answer is yes, then there is a great possibility that the drain vent pipe is obstructed.

When you have poorly vented pipes or they become clogged, the air pressure builds up and causes such gurgling noises.


Well the plumbing system is supposed to allow the air to escape through the vent. But if they can’t escape, the air finds the nearest exit like toiler or sink and makes such noise while escaping.

So, I would take this very seriously if my toilet makes such noise each time I flush it!

  • Slow Toilet Flushing

Everybody gets power flush toilets now that makes strong flushes to clear everything in the toilet bowl with a single flush!

But if it seems to make weak flush and it takes longer time than usual to refill, the clogged vent lines may be responsible!

This is not the only reason why your toilets may make such a weak flush. But if you have tried all the ways to make it flushes strongly and you did not succeed, you can suspect to have poorly vented pipes.

There are many unexpected things may be responsible to have clogged drain vent pipe like tree branches, leaves, bird nests, and even tennis balls!

Whatever the reasons, you should take immediate action to clear the clogged vent pipes. You can call a professional plumber to clear it and I strongly recommend doing so.

But if you want to clear the clogged vent pipes yourself, make sure you know what you are doing to prevent further damages!

Plumbing Vents: Why It’s So Important?

fixing blocked kitchen sink

Let’s see why you should take those symptoms seriously. Understanding how the plumbing vent works will motivate you to take preventive measures to keep it functioning always.

First, let’s see how it works.

Well, it’s a vertical pipe. Being a vertical pipe, the plumbing vent attaches to the drain line and runs through the roofs of your home to disperse all the bad smells.

Professional plumbers refer to the vent pipe that leads to the roof as the vent stack. The vent stack plays the main role to maintain the pressure in the waste system of your house and dissipates the gas into the air through the pipe.

The entire plumbing system of your house is comprised of vent systems and drainage systems. They work together to remove water and waste from your home.

All the plumbing fixtures of your house like the toilet, bathtub, and sink need fresh air to function properly. The vent pipes ensure that and it also moves the waste through the drainage each time you flush your toilet.

The plumbing vents keep the water flowing from one place to another in your house efficiently. So, without functioning properly when clogged, your daily life will come to halt!

Your house smells nice not because of the air fresheners only. The drain vent pipe removes the odors and gas to keep it smelling nice too.

Such vents do so by regulating the air pressure in the plumbing system of your house. When those vents are clogged, the airflow becomes restricted and your entire house will smell terrible!

Frequently Asked Questions (FAQs)

Can a vent stack get clogged?

Yes! You will hear gurgling sound from the drains and there will be slow drainage. When you hear those signs, you have a clogged vent stack!

Do old houses have plumbing vents?

Yes they do have plumbing vents but they are not properly vented most of the time. And until the walls and ceilings are out, it’s difficult to tell how bad it is.

What are vent pipes made of?

There are certain approved materials like cast iron, copper, Schedule 40 PVC DWV, galvanized wrought iron and steel, Schedule 40 ABS DWV, brass, etc to make vent pipes.

What happens if toilet is not vented?

All the wastewater and solid waste (poop!) won’t move out of your house if the toilet is not vented properly. So, you will end up with various plumbing problems like backed-up toilets and overflowing drains!

Does plumbing go through the ceiling?

Yes. Many homeowners don’t like the idea but it’s a generally accepted practice to minimize the damages during the re-plumbing.

Can you pour drain cleaner down a vent pipe?

No, you should not pour drain cleaner down the vent pipe to prevent corrosions. If you have older metal pipes, drain cleaner like Drano will damage it severely.

Final Thoughts

Fixing a blocked vent pipe yourself is a time-consuming and difficult task. And as you have seen, it can cost you some serious money if you hire a plumber after things get worse!

But you can keep all those harassments at the minimum if you can successfully notice such symptoms of a clogged drain vent pipe and take preventive actions.

I hope this article comes in handy for you. Be alert!

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1 thought on “Symptoms Of A Clogged Drain Vent Pipe That You Never Should Ignore!”

  1. I think including adverts in the info, (most of which I found interesting – and might buy the product,) a great idea. I got the answer to my problem for nothing. I hope the advertisers contribute towards your costs. Thank you!!

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