How to Unclog a Vent Pipe | Full Process of Unclogging a Vent Pipe


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Can your sewage system drain wastewater easily? If not, something is probably clogged in the drain, such as food, hair, or even kitchen utensils. Another reason for slow leaks is a clogged ventilation duct. It is very important always to unclog the vent. In this guide, I will discuss how to unclog a vent pipe.

How to Unclog a Vent Pipe

In most cases, the ventilation duct comes through the roof. Look for a black pipe about three inches in diameter made of cast iron or PVC.

You will need a ladder to get to the roof. Follow all safety aspects of the ladder, make sure it is installed on a firm, level surface, fully open and locked, don’t miss the ladder warnings, etc. If the roof gets wet from the rain, postpone the work to another day for your safety. Many people choose to have a professional Cedar Rapids installer do this job because it is dangerous to work on a roof.

Take these tools with you:

  • Screwdriver
  • Flashlight
  • Garden hose
  • Plumber’s snail (“snake”)

To confirm that you identified the vent, ask someone to flush and listen for the flush.

If there is a ventilation cover, remove it with a screwdriver. You can see that the hole in the pipe is clogged with some dirt-like leaves. Removing the trash can solve the problem. If you don’t see any dirt above, spray the pipe with the hose nozzle on “Full” or “Jet.” This should clean the pipe, but water starts to come out of the pipe; you need to do more. For example, a bird or other animal can enter a pipe and die.

If the hose is not leaking, then you have to try the screw. (Recommended length is 10-20 feet). Gradually connect the cable until you reach an obstacle. Rotate the handle to slide the head through the lock. If you are successful, the water will begin to drain. Pull in the cable (a crowbar is usually included). Spray more water into the vent to make sure it is no longer clogged.

Clogged Vent Pipe Symptoms

How to Unclog a Vent Pipe

The signs of a clogged vent line are similar to a clogged leak, but what are the clues? Find out if the drainpipe is clogged by investigating the following problems:

Boiling and gargling

Does this happen when water runs down the drain? Does the toilet bubble after washing? 

This could signify that the air that is supposed to come out of the vent pipe is leaking. The bathroom vent pipe is clogged.

Slow drains

If the drain in your home is slow, it makes sense to assume that it is clogged. (The main sewer line can also be clogged, and if you suspect this is the case, seek help from Benjamin Franklin of the Cedar Rapids plumbing company.) However, if all the drains in your home are slow, it could be caused by clogged sewers. 

Read More: How To Tap Into Main Water Line

Duct odor 

If the air in a duct or bathroom smells like sewage, it can also signify that the exhaust duct is blocked. This creates a vacuum that pulls things the wrong way.

Top 3 Signs Your Plumbing Vent Is Clogged.

Top 3 Signs Your Plumbing Vent Is Clogged.

Air should flow freely from the tube through the tube to equalize internal pressure and allow water to move efficiently. If the water hole is clogged, you will feel like this:

  • The bathroom is splashing and foaming.
  • Slow drainage
  • There is a pungent smell of sewage.

The hum of the bathroom ventilation is insufficient due to obstruction and airflow. The pressure inside the system is greater than the air in the bathroom. When you flush the toilet, the system will try to balance the air entering and leaving the pipes.

This will shut off the water, and you may hear a gurgling or buzzing sound in the bathroom. Slow Release Increased pressure in the drain may prevent an average water flow if your home’s drainage is slower than usual. The problem may be due to insufficient or blocked ventilation. The drain hose may be clogged.

Strong sewage odors each collector has a water separator that prevents sewage from entering the house. But if the discharge pressure is too high, water will come out, and smell will come out. If you feel that there is a sewer in the house, it may be that the drainpipe is clogged.

Four Critical Warning Signs of Clogged Vent Lines

Plumbing is not easier than most people believe. Did you know, for example, that sewers need to be ventilated?

Chances are you didn’t. Few people know that they also have pipes attached to drain lines that allow exhaust, sewage, and air to pass through to ensure that leak pressure is equalized to ensure sewage flow. These pipes are known as vent pipes, and if clogged, they can create major problems in your home that may require the help of a local plumber. 

Here is an example of how things work. In a sink, water flows through a drain in a bent pipe called a P-siphon. The siphon is filled with water to prevent wastewater and odors from flowing back into the bathroom pipe. The siphon p is renewed when more water flows through it. A drainage pipe is connected to the p-siphon. It goes through the wall in a mound of earth, where the sewage flows through another pipe to the sewer or septic tank, and the sewage gases reach the roof the pipe exits. 

When the vent line becomes clogged, it can lead to a variety of issues, including:

Read More: How To Connect PEX To Galvanized Pipe

Slow drain cleaning.

If the drain isn’t clogged and you’ve done your best to clear a possible blockage in the drain, the problem could be a clogged vent. Without air to equalize the pressure, the free flow of water through the drainage system can be restricted.

  • Water will not be able to flow correctly through the drainage system if the air vent is obstructed. This can cause siphons under sinks or toilets to dry out and collect exhaust gases, which can cause unpleasant smells throughout the house.

Loud noises

If your sinks or bathtub makes noise after a leak, there is a high possibility that the vent line is clogged. Air pressure built up in poorly ventilated pipes can cause pipe noise.

Low Rinse

If the water flow in the bathroom seems weak and the dishes do not fill quickly enough after a wash, the vent lines may become blocked. Poorly ventilated drains aren’t always the cause of toilet malfunction, but if you run out of other explanations, they could be the cause of your problem.

Professional plumbers companies can inspect the vent lines and confirm that their suspicions are justified. If the vent line is blocked, installers have several options to correct the problem. You can use special installation tools, such as screws to overcome clogs and restore the function of the vent line.

How to Unclog a Vent Pipe: FAQs 

What happens if the vent pipe is clogged?

If the vent is clogged, the air cannot properly escape the plumbing system. In this case, the air will find the closest outlet, usually a toilet or sink. It makes a sound as it flees, which causes gurgling noises.

Can you pour Drano on the vent?

If you don’t have a suitable drainpipe, you may be looking for an easier solution. Can a sewer cleaner be inserted into a vent pipe? Any plumberwill tell you to avoid a cleaner like Drano at all costs.

Is the vent pipe blocked?

The ventilation system (water pipes coming from the roof) can be blocked. When a vent becomes clogged, it will show up in your home several ways, from “ghostly washing” the toilet to a sink that doesn’t drain properly. The vent pipe can get clogged due to a variety of things, such as bird nests.

How much does it cost to clean a vent pipe?

Cleaning the pipelines costs an average of 100-200 UAH.

Is a blocked vent dangerous?

Clogged vents can lead to a build-up of sewage that can make you or your family sick. In cold climates, the exhaust from the pipe contains water vapor, which forms a layer of ice that can become thick enough to cover it at the end of the pipe. Excess snow on the roof can also block the vent pipe.

How do you open a ventilation pipe without a roof?

Insert the end of the auger cable into the pipe. The snail is commonly referred to as the plumbing coil because of the flexible cord that runs through the pipes. Turn the worm handle clockwise to pull the cable through the tube until it hits the lock and breaks it.

Can clogged ventilation cause the bathroom to overflow?

If you find the bathroom clogged more often, a clogged ventilation duct may be the cause. The vent pipe directs outside air into the plumbing system to replace the air that is blown out with every wash. If it’s blocked, your bathroom won’t flush properly, resulting in a spill.

Do ventilation ducts have to be covered?

Residential units cannot be used with the plumbing vent pipe attached. If a plumbing vent pipe is blocked (by a lid, bird’s nest, or ice cap), air will not get into the drainage system, so the siphon will not pressurize water from the sink’s siphons.

How to snake roof ventilation?

Lift the 20-foot sewer auger onto the roof. Insert your head into the opening and push in until you encounter resistance. Rotate the handle so that the head goes over the obstacle. Once removed, there should be no more spills or high water levels in the sewer or bathroom.

Can the bathroom vent pipe have an elbow?

They may have vents, but you still can’t use a 90-degree elbow – sometimes called a “vent elbow” – if the hinge is below the level of water that is usually in the sink. A fitting called “T-Shirt Sanitary” seems to work, but it doesn’t.


Unclogging the roof vent pipe is a great job, so if you have a drain plug, there’s no need to call a professional plumber. Save money and auger the venting of roof pipes.

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