Top 5 Signs of Clogged Sewer Line (Key Causes & Fixes)

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Are you having significant issues with your bathtub, toilet, or kitchen sink? You wonder what the cause is. Maybe you have heard stories of how clogged sewer lines can significantly contribute to this threat.

It’s challenging to figure out plumbing issues, especially if you are unaware of the exact problem. But you can solve this if you know the cause of it and if you can detect the different signs of a clogged sewer line.

In this article, we will be looking at the different symptoms of a clogged sewer line, what causes a sewer line to clog, and what you can do to unclog your sewer lines.

Let’s get started!

Causes Of Clogged Sewer Line

First, before delving into knowing the signs of a clogged sewer line and repairing it, it is crucial to learn the underlying cause of the blocked sewer line so you can find your way around the solution.

It is wrong to guess the cause, as this would lead to constant and expensive repairs.

See Also: Signs of a Clogged Septic Line

1. Debris, food waste, and hairs

Although it is almost hard for debris to cause clogging, it is possible because as long as the debris compounds, it forms clumps in the main sewer line, which will undoubtedly result in a clogged sewer line.

Another thing that can cause clogs in the sewer line is food waste. Like leaves and other debris, food waste can clog the sewer line.

This is most common in homes where children gain direct access to the sink or toilet. The careless dropping of food in the drain can cause clogging.

It is almost impossible for hairs to cause clogs in the sewer line, but just like debris, if it compounds and goes unchecked, it would cause significant issues.

2. Greases and fats

Another root cause of clogged sewer lines can be greases and fats; these, when they are liquids, can easily pass through the drain; however, once they are blocked, they can form clumps which end up blocking water or other liquids from passing the drain to the main sewer line.

3. Sands

This can be very relatable for households with sand around their homes; although it is excusable when you flush down the sand in the drain, it forms a clog, and as long as it is not attended to or stopped on time, then it will cause clogs in the sewer line.

It should not be flushed down the drain, whether clay or sandy soil.

4. Broken sewer pipeline

The sewer pipeline can be made of plastic, cast iron, or clay. If the pipe breaks into the sewer line for any reason, it will disrupt the activities in the sewer line as it would encourage clogs. This is most common with clay pipelines.

5. Tree roots formed in the main sewer line

This is a rare cause of clogged sewer lines; however, so long as you can locate trees around the main sewer line and all the grounds, as mentioned earlier, are not the cause of the clogs, then the reason is not far-fetched.

Trees can, on the journey to spread roots, find their way around or in the main sewer line, and as long as the sewer line does not lack moisture, the tree roots will continue to grow. The tree roots can catch a lot of debris, tissue clumps, and other wastes.

This will, in return, affect the secondary drains;

  • Toilet drain
  • Shower
  • Bathtub
  • Kitchen sink

So now that you know what can cause a clogged sewer line, how do you know your sewer line is clogged? Let’s learn.

Notable Signs Of Clogged Sewer Line

You will notice a few signs when your sewer line is clogged. And although at first, the signs may seem ignorable, it is essential to pay attention to them.

This way, you can know the underlying cause of the clogged system. You could avoid the constant repairs that may arise if or when the underlying problem is not solved. So what are these notable signs to look out for if you suspect you are experiencing a clogged sewer line?

Below are some of the most common signs of clogged sewer line:

1. Secondary fixtures drain slowly

Every drain in your home, from sink to bathtub and toilet are secondary drain connected to the main sewer line. So, they are designed to send water to the main sewer lines for every flush.

But if these fixtures drain slowly, it is a notable sign of a clogged sewer line. You are likely to experience this sign in the toilet and the bathtub.

Your drains immediately take water to the main sewer line with one flush, but if it takes time to drain, there is cause for it. You will need to check other fixtures to see if it is only the bathtub drain or toilet drain displaying this fault.

2. Water comes back after flushing

Another notable sign of a clogged sewer line is water coming back up in the drain after flushing any of the systems. The toilet is almost the first place you notice this sign anytime it is in use.

And when this repeats consecutively, it means you are likely experiencing blockage in the main sewer line.

Where are other places you are likely to experience this? Well, you will not just experience this in the toilet; you can also have water in the bathtub, kitchen sink, and when you try to use your washing machine.

Once your sewer line is clogged, it will affect the secondary pipelines, making it uneasy for water to flush properly.

If you ignore this sign, it will create a foul odor because the water waste is now hazardous, having gone through draining and coming up again.

3. The sewer cleanout has drainage appearing in it

The sewer cleanout is a pipe always connected to the main sewer line. This gives the plumbers access or treats matters as clearing blockages.

How do you find the sewer cleanout pipe? It is easy to detect for many homes as the sewer line is placed chiefly outside the houses. You can also find it in the basement, marked by a round or rectangular cap.

What should you do if the sewage comes from your sewer cleanout pipe?

If you have found your sewer cleanout pipe, look around for any sewage standing out in the sewer cleanout.

If you find water surrounding the pipe or draining out of the sewer cleanout pipe, it is another sign of a clogged sewer line. Leaving the system unattended can cause damage, as it would keep releasing water you do not need.

Usually, it is beyond your control, and to avoid unplanned expenses and continuous repairs, it is best to call a professional plumber.

4. Having sewage in the floor drain

If the sewer line is clogged, it will be difficult for water to pass through or drain appropriately in the main sewer line. So the main sewer line will force out water from the secondary drains.

You will notice floor drains in the bathroom, kitchen, laundry room, and even the basement, and if this is the case, then it is another sign that the sewer line is clogged.

What are floor drains?

Floor drains are designed and connected on the floor, especially when standing water could be detrimental or hazardous.

And since the floor drains function to transport excess water out of the area, it would be difficult if the main sewer line is clogged. This is because there is no other place for moisture to escape.

Get a professional plumber to clear the main sewer line to escape the problems. Do not ignore this sign, even if it is periodic.

5. Your drains develop a foul odor

Remember that we said earlier that water coming back up in the drain could cause a foul odor in any system.

Once the sewer line is clogged, it will form stagnant water around the secondary drain, mainly due to forcing out water from the secondary drains. The foul smell will be prevalent if you ignore it.

How To Fix a Clogged Sewer Line

The best way to fix the clogged sewer line is to call professional plumbers. They have the requisite knowledge and can detect the underlying cause for any signs of clogged sewer lines.

Another way to clear clogs is to use hot and soapy water to flush down the clogs. But this can only work when the clogs are grease and fats. Hairs, sand, tree roots, and other debris cannot flush with hot and soapy water, so we advise you to get a professional plumber.

Tips for preventing clogged sewer lines

It is possible to prevent clogs in your sewer line.

  • Be careful to look at what you flush down your drains
  • Use toilet paper that can easily break down to avoid clumps
  • Check your sewer line every 1 ½ to 2 years
  • Use strainers in the kitchen


This guide successfully revealed the signs of a clogged sewer line. We understand it can be frustrating repairing plumbing issues, but you can also avoid constant repairs if you know the cause of the clogs.

You can also avoid outrageous spending if you can get a professional plumber to fix the issue. Always check your fixtures to detect signs that do not seem glaring but can cost you an arm and a leg.

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