What Causes a Belly in a Sewer Line?

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You may have a belly in your sewer line because of debris accumulation. The debris would cause blockage and not permit a free flow of water. Human error can also lead to belly in your sewer line, including poor installation and soil compaction.

sewer pipes

What is a Sewer Line Belly?

A sewer line belly refers to a blockage in a sewer line that allows the sediments to settle at the bottom, restricting the free flow of the sewage water.

Normally, sewer water should flow inside a sewage line in a downside position. When a belly surfaces in your sewer line, the water will flow in a backward direction.

Also, a bellied line will slope negatively. Hence, water often accumulated at the lower parts of the sewer line. Once water remains stagnant at a point, waste and other unwanted materials would continue to settle.

What Causes a Belly in a Sewer Line?

Several reasons contribute to belly in a sewer line, with the major one being the service of an inexperienced plumber. Hence, it is crucial to ensure a plumber is licensed before requesting such service.

Fixing pipes is not hard, as some laymen can carry it out after studying some tutorials. However, it is crucial to consider the plumbing code, as sometimes the pitch may be too much or not enough.

This involves providing enough line support to ensure it does not slip over an unstable ground over time.

Another reason that may cause a belly in a sewer line is improper compactness and if the pipe installation was not in the appropriate pitch. Natural causes such as soil leaching, temperature change, or earthquake can also cause a belly in a sewer line.

It can cause a shift in the soil position. The repair process for a natural cause usually takes a long time and procedure.

When you have an old pipe, there is a likelihood for the water to flow less freely. If your pipeline undergoes a lot of stress, it will degrade as it ages. The soil position would shift, causing an uneven flow in the pipeline.

Hence, a belly may surface in a particular section of the pipeline, leaving others unaffected. As a result, a plumber must do a check-up with a camera and identify the problem joint.

Also, this will prevent you from replacing the whole pipe, which may have cost you a lot. Replacement is necessary if the pipeline is old and worn out.

How to Fix a Belly in a Sewer Line?

You can either fix your sewer line traditionally or use the modern method. However, both have pros and cons.

The traditional method can repair extensive damage, but it is more time-consuming and costly. Sometimes, it may require removing the wall to fix the pipe.

However, this method is rarely available in cities than in less developed areas.

A trenchless sewer repair is quick and requires no damage cost. If the cause of the blockage is a sharp object such as a tree root, which has punctured the pipe, you need a replacement to prevent the water from overflowing. Hence, try to limit the number of trees surrounding your pipeline as much as possible.

However, if your pipe is just clogged, a professional can fix it using an auger without damaging the sewer line. A backward clog would require an advanced solving method, and if it affects more than one pipe. Other processes you can use include snaking and hydro-jetting.

Avoiding a belly in the sewer line starts at the planning stage. Hence, it is vital to use some materials such as stones or sand to prevent clogging.

This process is known as trenching, which stops the line from flowing in the negative direction. Also, workers should ensure to address the fundamental problem to prevent it from surfacing again.

How Much Does it Cost to Fix a Belly in a Sewer Line?

In fixing a belly in your sewer line, you need to carry out an excavation process, which costs vary depending on the method you are employing.

Generally, the trenchless method costs more than the traditional repair method during the application, but the traditional process costs more in the long run.

The traditional process costs about $8,000 but usually attracts an extra fee to fix the yard. Hence, the total amount often rounds up to $14,000.

On the other hand, the trenchless method costs between $7,000 and $12,000. It does not require extra spending since the process does not destroy the pipeline area.

Moreover, the cost of fixing a belly in a sewer line varies, depending on your location, the required repair process, and the company you are consulting. However, many plumbers accept an upfront payment before fixing the problem.

Also, a repair process that requires a permit would cost more than the regular. For instance, a public location or paved road would request some rights before digging up the area. All these would accumulate as the total expenses of fixing your sewer line.

Can Trenchless Sewer Repair Fix a Belly?

Trenchless sewer repair can fix a belly if it does not involve digging up the area. You either spin a line or spray your pipeline to free the obstructive material in the sewer line.

The spin line method is the safe call in extreme cases where there is usually no better alternative. However, traditional sewer repair is the most effective method among others. If the negative direction of your pipeline is very sloppy, you may need to replace the whole line, and the trenchless sewer would be ineffective in this case.

Also, techniques like pneumatic gopher and directional boring are not appropriate because of the underlying rocks.

An open trench method is appropriate in opening up the ground and fill the sagging area. After correcting the sagging area, you can strengthen joints by covering them with suitable materials.

On the other hand, trenchless sewer repair is less costly than the open trench method, and it is best for pipe replacement and not necessarily pipe belly.

However, many sewer bellies diagnoses are usually not correct. The fact that a water level is an imbalance does not mean a belly is in the sewer line. Sometimes, channeling is the problem instead of a belly situation.

In a channeling scenario, the pipeline bottom is low and maybe invisible from a far end. The cause of channeling is different, as it often results from corrosion and worn-out materials.

Erosion of the sewer bottom may give space for the invasion of unwanted objects such as tree roots. Also, the sewer channeling occurs more than the sewer belly and requires a different technique, particularly the trenchless sewer repair method.

Hence, it is vital to identify the real problem, to perform the right solution.


In conclusion, confirm a belly is present in your sewer line by using a professional camera for inspection. It will help you to avoid any unnecessary spending and stress.

A professional plumber can inspect the specific location of the belly with a camera. Then, identify the exact place that needs treatment.

Afterward, you can address the belly issue with the solutions aforementioned above.