If you noticed your toilet bubbling or gurgling after a separate drain is used, it is a common sign that your main sewer line is clogged.
All the drains in the home are connected to the main drain. To make it easier to understand, think of your drain configuration like a tree with all of its branches. Each branch (drain) leads into a tree trunk (main sewer). The main (trunk) sewer line collects all the waste from each fixture and then heads to the city sewer to dispose.
If you have a clog that is related to only one fixture (meaning the clog is only affecting one drain, not multiple,) this means it is only a branch drain clog.
If you have a clog that is affecting multiple drains or is backing up into another drain, this usually signifies the clog is deeper down the line.
When drains are connected, and one of them clogs, very often the water will surface at a low spot in the home.
The toilet and shower/tub are the fixtures that are typically lowest to the ground. Being that your main sewer line is located under the home, the lowest fixtures in the home are usually a toilet or tub/shower.
Why does the drain gurgle or bubble?
This happens because the drainage system is trying to get air to breathe. The vent pipes (the drainage pipes that stick out of your roof) not only allow sewer gasses to escape but also allow air into the drain to allow the drain to flow.
Think of a straw you would use for drinking. If you stuck the straw into a cup full of water, blocked the end of the straw, and then pulled it out, all the water would remain in the straw. Your drains work similarly, in that they need air to drain.
When using a drain that backs up into the other, this tells you two things:
1. The drains are connected together.
2. There is a clog in the drain line that supplies drainage to those two fixtures.
In the illustration below, you will see how two drains can be connected, and at what point the clog may exist.
As you see, if the drain connecting the kitchen and laundry drain clogs, it will affect both drains. Whichever fixture is located at the lowest level, the water will rise in that fixture.
Symptoms of a Clogged Main Sewer Line
-Drain gurgles or bubbles when being used
-Toilet backs up into the bathtub or shower
-Toilet gurgles or bubbles when flushed
-Toilet flushes slow or backs up into another toilet
-Sink or toilet gurgle when another drain is used
-Sink gurgles when washing machine is draining
-Toilet overflows when washing machine drains
-Shower or tub fills up when another drain is used
-When a drain is used it backs up into a floor drain or basement drain
How do I determine where the blockage exists in my drain?
There are 3 main reasons for a clogged main sewer line
1. Tree roots
Tree roots are the number one cause of sewer line clogs. Roots are very strong and can easily penetrate older sewer lines. Commonly, tree roots invade fittings that are weak in the pipe. When roots overtake the sewer line, water, debris, and solids can no longer pass through. Eventually, the drain backs up into the home.
2. Reverse grade or “Belly” in the Drain
(also known as low area, sag, or flat spot)
Reverse grade (belly) is when the sewer pipe slopes the incorrect way. This could be caused by earth shifting (earthquakes or other geological occurrences) which may add pressure to the pipe resulting in distortion. Bellies can also occur when tree roots push down on the sewer pipe in a particular area, causing the pipe to slope incorrectly. Bellies can also occur because of poor dirt compaction or human technical error. This happens when the sewer is originally installed.
3. Broken, Cracked, or Collapsed Drain Pipe
Broken or collapsed sewer lines can result from multiple causes. When roots invade a sewer pipe they can easily bust the pipe, resulting in a collapse. Earth shifting (earthquake) can result in a distorted sewer pipe. Serious ground movement can cause a pipe to completely collapse. Often, old age and deterioration cause sewer pipes to fail.
What should I do if I have a clogged main sewer line?
Leaving the drain unattended does not make the issue go away. When a sewer line clogs, it is important to address the issue immediately, to avoid water damage. If you are running a dishwasher or a washing machine when the main sewer is clogged, water may seep out of the bottom of the toilet and spread sewage all over the floor. For this reason, it is prudent to be proactive about this issue and take action before disaster occurs.
There are ultimately 4 things you can do when your sewer line is clogged:
1. Call a plumber to alleviate the drain clog and inspect the cause of backup.
2. Rent an electric drain machine (also known as a snake) from a local hardware store and attempt clearing the blockage yourself.
3. Use a chemical drain cleaner that you can purchase from the hardware store. (Although this method is not recommended by professionals, it is an option for you nonetheless)
4. Leave it, and hope the clog clears itself. (Although extremely rare, it can happen)
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If you are experiencing any of the symptoms we discussed in this article, and feel you may need professional help, let us know. We can help.