A gurgling sound from your sink is a sign that the plumbing is not installed correctly or that there are issues with the sink vent. It can also signify that your home’s sewer line is blocked. How do these issues happen, and if your sink makes a gurgling sound when it drains, how do you solve the problem?
It is normal for water to make a splashing or swishing sound when it leaves your sink. But a gurgling sound coming from your sink is abnormal. When gurgling sounds come from the sink, there is also a chance that you will have a problem with sewer gases finding their way into your home, warns Castle Management.
Why is your sink making a gurgling noise
The three main reasons why the sink might make a gurgling sound when water flows into it are:
- The sink is not vented
- The sink vent is blocked
- There is a blockage in the sewer line
The sink is not vented
Your home’s plumbing operates under the force of gravity and air pressure. When water enters the drain opening, the only way it can flow through the pipes is by displacing the air that is already in the pipes. Since water is denser than air, gravity can make it force the air inside the pipe downwards. This creates suction pressure behind the water.
When this happens, a zone of low-pressure forms within the pipe, creating a vacuum. Since vacuums do not generally exist in nature, air must enter the pipe to offset the imbalance in air pressure. If the pipe is properly vented, that air will come from outside the home through the vent. If the pipe is not vented, the air is sucked out of the P-trap, creating a gurgling sound.
Along with gurgling sounds from the drain, sewer gases may also escape from the drain opening and foul up the air inside your home. To solve this problem, you can install a vent under the sink after the P-trap. This can be connected to the central vent outside the home. It could also be a mechanical vent that sits under the sink and draws air from the surrounding area.
The sink vent is blocked
The pipe vent moves air from outside into the pipe and replaces air displaced when you flush water into the drain. But the vent can’t do this if it is blocked. A blocked sink vent is as good as not having a sink vent at all. The same problems when there is no sink vent happen when the sink vent is blocked.
Vents can get blocked if an animal dies inside it or gunk accumulates within the pipe. How do you know if your vent pipe is blocked? Several signs accompany this issue, including strange noises from the drain sink. Other signs to expect when a sink vent is blocked are slow drains and sewer gases finding a way into your home.
If you think your vent pipe is blocked, you need to clean it. Where the blockage is inside the pipes, this can cost between $100 and $200. The problem will only worsen if your vent pipe is blocked and not cleaned immediately. More debris can be sucked into the clogged pipe, making the problem worse and harder to deal with.
Blockages inside the sewer line
The sewer line that carries wastewater from your home to the municipal sewer lines is also connected to all the drains in your house. When there is a problem with the main sewer line, it can throw all the drains in the home out of order. A blocked sewer line can also manifest as gurgling sounds from the sink.
To know if the gurgling sound from your sink is caused by a blockage inside the main sewer line, check if all the sinks in the home are making this gurgling sound. Typically, all the sinks in the home will be affected if the problem is from the main sewer line. When this is the case, cleaning your sewer lines by way of hydro jetting is the only way to solve the problem.
What causes blockages in the main sewer line? There are many reasons why this can happen, but the more common ones are washing fats, oils, and grease into the drain; flushing food waste into the gutter; tree roots puncturing or growing around the sewer line, and corrosion inside the sewer line. Using chemical drain cleaners to clear your drain can also damage the main sewer line.
To conclude, if you hear gurgling sounds coming from your sink every time you flush water into the drain, you may be sure that your sink is not vented, the sink vent is blocked, or there is a problem with your main sewer line. To know the exact cause of the problem, you may want to have a plumber inspect your home sewer lines with a camera.