When it comes to the various components in a home plumbing system, few play as central a role as your main sewer line. The sewer line acts as a conduct from your home to your city's sewer main, usually located beneath the road in front of a house. Waste water flows out of your home through the sewer pipe en route to the municipal waste treatment plant.
If anything should go wrong with your sewer line, your entire home's plumbing system may be affected. One of the most frequent issues affecting sewer lines comes in the form of sewer line bellies. If you would like to improve your knowledge of this common problem, keep reading. This article outlines four things to know about sewer line bellies.
1. Sewer Line Bellies Impede the Flow of Waste
A residential plumbing system contains no pumps or other mechanical parts responsible for pushing waste to the city sewer main. Instead, gravity alone ensures the proper flow of waste out of your home. In order to facilitate flow, the sewer pipe leads out of your home at a sloping angle. Ideally, the sewer line should have an angle of ¼ inch for every foot of pipe.
A sewer line belly involves part of the sewer line sagging downward, taking on a curved shape which impedes the natural flow of waste. Not only does the waste water no longer have the benefit of flowing downhill all the way to the sewer main, but it also has to move upward along the second half of the curve.
In some cases, the pressure of the water flowing out of your home may provide sufficient force to push past a sewer line belly. Yet over time, debris tends to build up along the base of the belly. This build-up makes it harder for waste to move through the sewer line. Eventually you may begin experiencing sewage backups inside of your home.
2. Sewer Line Bellies Usually Have Natural Causes
Most home sewer lines start off with a correct angle. Yet as the years go by, those pipes often develop bellies as the result of shifting soil. As dirt compacts beneath the sewer line, it will sag downward into any void spaces that form. A variety of natural causes can lead to sewer bellies, including tree root growth, excessive soil hydration, earthquakes, and even normal seasonal temperature fluctuations.
3. Proper Installation Techniques Prevent Sewer Bellies
While the factors that lead to sewer bellies tend occur naturally, well-installed sewer lines can often resist such forces. To begin with, contractors should thoroughly compact the soil before installing the sewer line. Compaction minimizes the likelihood of soil-density changes leaving the pipe under-supported.
An equally important tactic involves installing a bedding material in the trench before placing the pipe. Sand makes the best choice for a bedding material, although gravel can also be effective. Unlike soil, sand will not compact over time. As a result, the base of the sewer pipe should maintain a decent level of support.
4. Many Sewer Belly Diagnoses Are Incorrect
Contractors often use video inspection technology to diagnose sewer bellies. Unfortunately, less experienced plumbers often misinterpret what they see. Noticing a dip in the water level at a certain place in the pipe, they assume they have found a sewer belly. Instead, your pipe may suffer from the problem known as channeling.
Channeling happens when the bottom of a sewer line erodes, leading to low spots. In extreme cases, the bottom of the pipe may even disappear entirely. The issue here has nothing to do with slope, and everything to do with corrosion and wear. Repairing channeling, therefore, requires a much different repair procedure than repairing a sewer belly.
For more information about keeping your sewer line in good working order, please contact the home plumbing pros at Dave-Co Plumbing.