Why Is My Drain Gurgling?

South End Plumbing, Heating, & Air Expert Tips

Why Is My Drain Gurgling?

And what you can do about hearing that dreaded sound.

What Causes a Drain to Gurgle?
What Causes a Drain to Gurgle?

You may be here because you’ve started hearing strange gurgling sounds coming from your drain, often in your tub. The curious thing is you’re not using your tub at the time, you might be flushing the toilet, using the sink, or taking a shower. All of your drain pipes connect, so you know there’s a commonality there but gurgling sounds are not normal and it could be a sign of a clog or partial clog. The bad thing is these type clogs only get worse over time.

So What Makes the Drain Gurgling Sound?

Drain gurgling occurs when there is a clog (block), and even a partial clog, preventing air from flowing through the drain. 

No matter if the gurgling sound is coming from your sink, toilet, or shower they all have the potential to be clogged. The next question is to gain an understanding of what could be causing the clog.

Clogged or Partially Clogged Drain

The main cause for a gurgling sound in a drain is a partially clogged or fully clogged blockage in the drain pipe. these two are distinctly different and how to treat and the possible causes.

A partially blocked drain

If you do have a partially clogged drain then you need to understand that a completely blocked drain is coming soon. This will cause the water to drain much slowly and the action of that slower draining water will wind up allowing the clog to build up faster. If you do start noticing a slower drain you’ll want to take action to clean the drain as soon as possible. South End Plumbing carries a few different products including BIO-Clean but you can also use baking soda and vinegar in a mixture as described in this article here.

A completely clogged drain

If you wind up letting a partial clog build up to the point that the blockage is more significant then water will begin to back up in the drain and overflow into the sink or tub Etc. there are many causes that can contribute to a complete clog.

  • Dirt
  • Hair
  • Soap residue
  • Toilet paper and waste back up
  • Dead skin

Clogged main sewer line

Belly in a Sewer Line
Belly in a Sewer Line

The main sewer line is the larger diameter pipe that all of these smaller drains run into in your home. This large mainline carries the waste water from your house to the city sewer line or a septic tank in your yard if you have one. If you do have a clog in your main line some people will begin to notice backups and their lower floor levels either on the first floor or in a basement. For most main clogs you’re going to have to hire a professional plumber to snake the drain with a drain clearing machine.

Some Of the main reasons for main sewer line blockages are as follows:

  • A belly in the line that allows waste to build up
  • Roots growing into the line
  • Broken main line pipe

During the time of a home’s construction pipes are laid in the ground and the soil underneath will give way or compact at a different rate and create what’s known as a belly in the line. This is a spot where the pipe will have a sag in it and that sag allows for debris and sewage to collect.

One of the reasons that tree roots find their way into main line pipes is that once there is a crack in a pipe, a tree root will seek out the water coming from the crack because routes are designed to go towards water source. Once they find a crack and start going inside the crack they can increase in diameter and make the crack larger and larger. This allows the roots to start growing inside the body of the pipe and over time will fill up the entire volume.

For broken pipes it’s pretty obvious that there can be a clog that forms very quickly because even if there’s no tree roots around to invade the pipes then you can certainly have mud and soil that starts creeping in and building up. This effect compounds also due to the displacement of the break, more water escapes which creates more mud. Very quickly the mud surrounding the pipe can enter into the pipe. This is also how sink holes are create that you may see in parking lots from time to time. 

That being said there are many different products that you should not flush down the toilet this is because not only for their odd shape but they are not designed to break down in water like toilet tissue does easily.  The likelihood of an accumulation of these type of products can very easily cause a clog.

  1. Baby wipes
  2. Female hygiene products
  3. Q-Tips
  4. Diapers
  5. Tissues
  6. Dental floss
  7. Paper towel
Drain Vent Pipe Diagram
Drain Vent Pipe Diagram

Clogs in a Vent Pipe

Have you ever taken a jug of water and tried to quickly pour it out? The rate at which it comes out is inhibited by the amount of air that can be displaced inside the jug and this creates a “glug glug” type sound. In theory if you had a hose vented from outside the spout going to the bottom of the water jug the water will pour out instantaneously. This is the theory behind having vent pipes in a drain system. Behind the walls of every home there are vent pipes that connect to drains that exit out the top of your house. If for some reason they get clogged with a dead animal or a bird’s nest – the same  action that happens with the jug will be happening with your drain lines.  This can cause a lot of problems because air can get trapped and may potentially cause wastewater to be slowed down which can in turn caused clogs to more easily form.


If you ever problems with clogs of any sort, we are just a click away. Also if you would like have your drains inspected – give us a call! South End Plumbing is one of the only companies that will give you a free estimate. Call us at 704-919-1722 or fill out the form online to schedule a visit.

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