Symptoms of a Clogged Plumbing Vent & How to Unclog

Drain vent pipes are meant to balance the pressure between the inside of the pipes and the air outside. This allows gases and liquids in the pipes to flow freely with the wastes and dirty water flowing to the drain as the air escapes to the environment.

The drain vent pipe is usually a pipe running from a section of the plumbing system in the house and rising to a section above the roof. This pipe can get clogged up for various reasons such as the accumulation of leaves, corrosion, bird nesting in it and other reasons.

Knowing how to identify the clog and how to unclog the vent pipe will help you restore the normal workings of your plumbing system. Below, we take a look at some of the symptoms of a clogged vent pipe and how best to unclog the vent pipe. Keep in mind that, while you can carry out the unclogging by yourself, other cases will require the input of an expert.

Symptoms of a clogged drain vent pipe

Some of the signs telling you that a vent pipe is clogged include the following:

A slow drain rate

When the vent pipe is clogged, there is an unequal pressure between the inside of pipes and the outside environment. Often, there is too much pressure inside the pipes compared to what is outside of them. This heightened pressure has the effect of making the sinks and tubs in the house drain slowly. If you notice that water takes longer than usual to drain from the sink, that could be the cause.

Plumbing Vents
Vent Pipes

Gurgling toilets

With a clog in the vent pipe, the air pressure in the pipes will be higher than what is on the outside. This can be observed when toilets gurgle either on their own or when you flush them. This is because air will try to escape through the toilet since the rest of the plumbing unit will be a closed system.

Sewer smell in the house

The vent pipe is usually the only part of the plumbing system where gases escape to the outside. The closest options are usually the toilet where there is a water trap keeping the gases from flowing into the home. When the vent pipe is clogged, the high pressure in the pipes can force its way through the pipes into the home through leaks and even the P-trap of toilets.

A weak toilet flushing

If your toilet bowl takes too long to refill after you flush it, it can be a sign that the water in it is struggling to fill the P-trap given the high pressure in the pipes. This is quite hard to notice since most people leave the toilet before the toilet can refill the P-trap and the toilet tank. It’s thus best noted in relation to the other signs on the list.

With these signs in mind, you should find a way to unclog the vent pipe to restore the normal functioning of the plumbing system.

How to unclog a vent pipe

A vent pipe can get clogged due to various reasons among them nesting birds, dead rodents and birds, leaves and debris, and even tennis balls in the pipe. All of this can be removed from the vent pipes with ease thanks to the simple nature of the pipe. However, for the complex vent pipes such as those with bends and junctions, you should always call in an expert.

Some methods you can employ to unclog a vent pipe include the following:

1. Remove debris and leaves

If the clog is just at the entry of the vent pipe on the pipe, you can simply remove it by hand or with a pair of tongs and the vent will be open again. For the clogs deep inside the vent pipe, head over to the next options.

2. Using a pole

If the vent pipe is a straight one and it has a nest, leaves or twigs, it will make sense if you either poked the dirt downwards into the drain or used the pole to draw out the debris. If you poke it downwards, it’ll join the rest of the sewer materials and compost with it.

3. Use a hose pipe with water

You cannot reach all the clogs in the vent pipes and some might require flushing them down the drain with water. You simply get a hose pipe, fit it into the vent pipe then poke the dirt as the water flows into the vent pipe. The poking is meant to dislodge the dirt then the water helps it flow away into the sewer.

4. Use an auger or snake

For the very complex types of clogs, you can always get a plumber’s auger or snake then use it to dislodge the dirt in the vent pipe. In most cases, the dirt will come out after a few trials.

As stated before, if the clog needs breaking down the wall or you simply can’t identify it, you need to get a plumber to do it for you.

Using a snake to unclog plumbing vent

Further Reading: How to Vent a Toilet

Tips to Prevent Plumbing Vent Clogging

To save yourself the trouble of having to deal with a clogged vent pipe and bad odors in the home, you should do the following:

Keep the top of the vent pipe covered

This doesn’t mean you should seal the top of the vent pipe airtight. Rather, you should have a cover a short distance from the opening of the vent pipe. Upward-facing exhaust pipes are the best example as they allow smoke to escape but not rain or debris to fall into the vent pipe.

Give the vent pipe distance from the top of the roof

At times, snow and leaves can buildup on the roof to the extent that they cover the end of the vent pipe and prevent the outflow of gases to the environment. This requires having a vent pipe is long enough such that no amount of snow or debris from trees can grow high enough to cover its top.

Clean the roof often

To prevent the buildup of snow and other debris on the roof to the extent that they affect the open end of the vent pipe, you should clean the roof often either by cleaning snow off it or pulling off leaves.

With these tips in mind, you can keep your vents working no matter the season or prevailing condition.

Benefits of Keeping Vent Pipes Clog-free

Venting pipes carry gases from the drainage system. These gases can be anything from toilet odors to other gases in pipes. They then deliver them above the roof where they mix with other gases making it almost impossible to smell them from indoors or even when outside the house.

For this reason, they should be free of clogs since these gases will find another way to exit the pipes if they’re not given a way out. In fact, they will find small cracks in pipes and even exit through the toilets indoors making the house unpleasant.

Another reason why vent pipes need to be clog free is that it keeps the inside of pipes at normal pressure. Without a balance of pressure between the pipes and the atmosphere around the pipes, pressure will build up inside the pipes with time. The pressure can force the awfully smelling gases back into the house through the toilets and sinks making the house smell badly. This can be observed through gurgling toilets and bad odors indoors.

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