What is Belly in Sewer Line?

Last Updated On June 11, 2024

Updated on March 21, 2023



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What Is a Belly in Sewer Line

Did you hear someone say that you have a “belly” in your sewer line? You may not know exactly what a bellied pipe means or what to do with that information. Don’t just ignore the situation. Learn what it means to have a “belly” in your sewer line and how it can affect your system.

In this PlumbingNav guide, we will cover:

  • What is a belly in a sewer line?
  • What causes a belly in a sewer line?
  • How serious is a belly in a sewer line?
  • How to fix a belly in a sewer line.
  • How much does it cost to fix a belly in a sewer line?

What's In This Guide?

      What Is a Belly in Sewer Line?

      A belly in your sewer line is a dip or sag in the sewer line. Sewer lines require proper angles and slope in order for water to transport through the pipes properly. Waste water will easily flow down into the belly, but it takes more effort for it to get up on the other side. 

      If you hear that you have a belly in your sewer line, beware of a misdiagnosis. In many cases, a belly in your sewer line is actually channeling. If you aren’t sure, get a proper sewer line inspection before you take action.  

      Watch: This video shows the role of slope, and also how a belly can restrict flow.

      What Causes a Belly in Sewer Line?

      The main reason that your sewer line may get a belly is that the soil around the sewer pipe changes and settles over time. This weakens the structural support that holds the pipe in place. Over time, the pipe sags.

      Another problem that can cause belly sag is when the sewer pipe leaks at one of the connectors. This erodes the soil and over time causes the soil to sink. The pipe then sags as it loses its support.

      You can eliminate a belly in your sewer line with proper installation and grading. When a plumbing service comes to install your sewer line, they will make sure to pack down the soil as tightly as possible to ensure you don’t experience a lot of movement. Of course, this assumes proper design of your sewer lateral the first place.

      How Serious is a Belly in Sewer Line?

      The seriousness of a belly in the sewer line depends on how deep the belly is and how much pressure your system generates to force the water through the belly. 

      In many cases, the belly will hold standing water and sediment buildup, which can lead to damage to the pipe. Older sewer pipe materials such as clay and cast iron can experience cracking, separation, and deterioration as a result of shifting soils and standing water in the belly. 

      If the water and eventually debris can’t get past the belly, you may also experience sewage backup. 

      While many of the problems that develop as a result of a belly in your sewer line are obvious, it’s best to get a sewer inspection to pinpoint the location of the problem and the extent of the damage.

      How to Fix a Belly in a Sewer Line

      In most cases, you will need to completely repair the sewer line if the belly starts to impede regular water flow or cause a broken sewer line. 

      Since sewer lines are so deep underneath the ground, it’s a rather large-scale project. 

      Instead of the traditional methods of digging into the ground to repair the sewer line, you can explore trenchless sewer line repair techniques, such as pipe relining or pipe bursting.

      Trenchless sewer repair offers a less expansive and less expensive sewer repair method compared to old methods. 

      CIPP pipe lining involves pouring material into the host pipe and then letting it harden into a new pipe. 

      Pipe bursting involves feeding a new pipe into the old pipe’s place, damaging the old pipe along the way. 

      These are ideal solutions to fix a pipe belly. However, excavation of the surrounding soil might be necessary if the underlying issue is related to settling and grading. In this case, the trenchless options above may not be the best solution.

      Also be aware that if other fittings or outlets are connected to the sewer line, additional steps might have to be taken.

      You may need to locate where the sags are by using a pipe inspection camera. These can be rented, or a professional plumber can provide this service.

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

      Replacing the belly in your sewer line can cost quite a bit of money, depending on the length of pipe that requires replacement. Longer sections will cost more. The cost is still much lower than traditional sewer replacement methods. 

      See the following trenchless pipe replacement prices:

      • Pipe bursting – $40 – $80
      • Sliplining – $80 – $170
      • CIPP – $25 – $65
      • Modified cross section – $18 – $50

      Is a belly in sewer line covered by insurance?

      A lot of variables contribute to whether or not home insurance will cover the plumbing cost of sewer line replacement, including the age of the sewer line, the sewer line material, your specific insurance policy and riders, and the location of the belly. 

      Furthermore, since your sewer line may connect to the city sewer line, the city may also have a program to help with the cost or even cover the cost completely. Reach out to them to ask, because any help in the form of a grant or assistance program will help tremendously. 

      If you’re in a new home, the builder might be on the hook for poor installation that results in the belly in the sewer pipe. This is typically within the first 10 years. Check local construction laws for specifics in your state.

      FAQS on Sewer Line Bellys 

      How serious is a belly in a sewer line?

      A sewer belly in the sewer line typically requires sewer line replacement, which can turn into a rather large job. 

      What does it mean to have a belly in a sewer line?

      A belly in your sewer pipes refers to an indentation or a sagging part of your sewer line. 

      How do you fix a sagging sewer line?

      To fix a sagging sewer line, you should consider trenchless sewer line repair methods, such as sewer line relining. 

      Is standing water in sewer line normal?

      No, standing water in your sewer line is not normal. The standing water can negatively impact the pipe material over time. 

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      About Plumbing Navigator

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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