What type of pipe is used for sewer lines?
Most of us hardly ever think about our sewer lines unless there is a problem. You know, out of sight out of mind.
However, you should not forget about your sewer line. Replacing a sewer line or even dealing with the consequences of a bad sewer line—sewer backlogs, leaks, and slow drains—aren't cheap.
At a minimum, you should have your sewer lineinspected and cleanedat least once every 2 years, especially for old tubes. This allows you to identify and fix sewer line problems before they become a bigger problem and more expensive to fix.
A sewer line inspection will also help you know what type of sewer pipe you have. A camera connected to a flexible cable is inserted into the sewer and a monitor on the surface shows the exact condition of the sewer pipe.
Sewer lines are made of different materials. The type of sewer pipe material installed on a property largely depends on when the sewer line was installed.
There are 6 types of sewer pipe materials. They are:
- Clay sewer pipes – Ceramic
- Cast Iron Sewer Pipes - Thick Metal
- Orangeburg Sewer Pipes - Fiberboard
- PVC Sewer Pipes – White Flexible Plastic
- ABS Sewer Pipes – Heavy Duty Black Plastic
- Concrete sewer pipes - Reinforced concrete
Cast iron is the strongest sewer pipe. A 4-inch diameter pipe can withstand 4,800 psi (pounds per square inch) of pressure. However, it is prone to corrosion, which weakens it over time, and it also infiltrates tree roots, causing clogging and sewage buildup.
PVC and ABS drain pipes are most preferred in modern plumbing. They are inexpensive, easy to install, do not corrode, and most importantly do not infiltrate tree roots. As such, PVC drain pipe outlasts all other types of drain pipe.
Sewer line pipes are typically 4 inches in diameter and are installed sloped toward the public sewer line or septic tank with a minimum slope of 2% (1/4 inch per foot of pipe). However, larger sewer lines (6 inches in diameter or larger) are used to service multiple homes or businesses.
Types of sewage pipes
And now let's look in detail at all types of sewer pipes. I hope that by the end of this post you have understood how each sewer pipe works and what are its advantages and disadvantages.
|Molten iron||Forte||Infiltrated by the roots|
easy to install
attacked by roots
hard to cut
Attacked by tree roots
Not suitable for DIY.
|PVC y ABS||Not attacked by tree roots.|
Smooth interior (some clogs)
lasted a long time
1. Cast iron sewer pipes
Cast iron sewer pipes are found mainly in older houses. Some modern houses still have them, but they are not installed as often as plastic sewer pipes.
The main advantage of cast iron sewer pipes is their strength. As mentioned, these tubes can withstand up to 4,800 pounds per square inch of pressure.
Although sewers generally do not exert as high a pressure, you can usually be sure that if heavy objects are shifted over the top of the sewer pipe or if there is a displacement of soil, the sewer line will remain intact.
The main disadvantage of cast iron sewer pipes, as well as other items made of cast iron, is that they are prone to corrosion and rust. When this happens, the tube begins to weaken, especially around the tube joints.
Small cracks/fissures start to appear and sewage starts to seep through. As you know, tree roots will naturally grow towards sources of water and nutrition. Household waste provides just that.
The roots are forced through the cracks and once inside the tube they multiply rapidly due to the presence of moisture and nutrition.
Tree roots inside sewer pipes are among the leading causes of sewer clogs. The solids in the wastewater get trapped by the roots, causing clogs and eventually the wastewater makes its way back into your home.
Unlike plastic pipes, the interior of cast iron sewer pipes is uneven, which encourages debris buildup and ultimately clogs. This happens especially when the tube is corroded.
Another thing worth mentioning is that cast iron sewer pipes are quite heavy and difficult to cut. As such, you need specialized equipment to cut and lift the tubes, and are therefore not suitable for do-it-yourselfers during installation.
Cast iron pipes are also quite expensive, especially when compared to PVC or ABS pipes. To put that in perspective, a 10-foot 4-inch cast iron pipe will run you up to $60, while a similarly sized PVC pipe is only $20.
2. Orangeburg sewer lines
Orangeburg pipes, also known as bituminous fiber pipes, are also installed in older homes. They are made from wood pulp and waterproof adhesives and then sealed with coal tar.
These sewer pipes were installed extensively during World War II due to a shortage of cast iron. They also became very popular with plumbers of the time, as they were lightweight and easy to cut.
Orangeburg sewer pipe installation continued until the 1970s when alternative and better materials for sewer lines became available. Nearly all installed Orangeburg sewer lines would need replacement today.
The main challenge with Orangeburg sewer pipes is their durability. They are the least durable sewer pipes and few of them can last more than 50 years.
In fact, these pipes were not originally designed for use in wastewater. They are made for dry use in the electrical and telecommunication industry.
Over time, it was noticed that the pipes used to transport the sewage ruptured, a condition also known as gumming. When the sewer pipe sags, the slope of the sewer line changes, which means that gravity cannot carry the sewer, leading to blockages and clogs.
Seepage from tree roots is another factor that causes Orangeburg's sewers to deteriorate more quickly. That is why they are almost never used nowadays.
3. Clay sewer pipes
Clay drains are another type of drain found in older houses. They were used before and during World War II. They are not as popular as before, so the bust can still be worn.
The main advantage of clay sewer pipes is that they are inert (chemically inactive). This means that they are highly resistant to chemical degradation (unlike cast iron sewer pipes).
The average homeowner will not install a clay sewer pipe as a DIY. It takes skill to know how to cut and they are also quite heavy.
Clay, being so porous, means that it attracts a lot of tree roots. The tree roots push it hard and after a while the pipes give way to the pressure and start to crack.
If you have a clay sewer line, you will always have to deal with tree roots inside the sewer pipe. Again, this will result in clogs and an eventual sewer buildup.
Clay sewer pipes, unlike cast iron pipes, have low strength and are prone to cracking or breaking under pressure. Therefore, you should avoid moving heavy machinery above the sewer line if you have these types of sewer pipes.
4. Concrete sewage pipes
Although not very popular, reinforced concrete pipes are the most preferred sewer pipes in modern plumbing, after plastic sewer pipes. They are used in both sanitary sewer systems and storm sewers.
Reinforced concrete sewer pipes can last up to 100 years or more. Not surprisingly, most municipalities and contacts are beginning to appreciate them more.
Unsurprisingly, concrete sewer pipes are bulky, difficult for the average homeowner to cut and install, so you'll need to work with a professional to install them.
On the plus side, reinforced concrete sewer pipes are affordable and have great strength. Therefore, they last a long time with fewer problems.
5. PVC and ABS sewage pipes
If you are considering replacing your sewer line, these are the pipes to consider. PVC (polyvinyl chloride) and ABS (acrylonitrile butadiene styrene) have many advantages and few disadvantages.
The main difference between PVC and ABS is that PVC is white and very flexible, while ABS is black and stronger and will therefore withstand more impact.
Whichever tube you choose between the 2 to use for a sewer pipe will serve you very well. Remember that the 2 use different adhesives to connect the 2 tubes.
The main advantage of PVC and ABS sewer pipes compared to other pipes is their longevity. Plastic pipes, as you know, are resistant to corrosion and waterproof, and therefore will not be affected by water in any way.
Unlike cast iron, clay and Orangeburg pipes, which are infiltrated by roots, roots cannot access the inside of plastic pipes. This means your sewer line won't crack, and more importantly, it won't clog on a regular basis.
It is important to mention that plastic sewer pipes are so smooth that they increase the flow of sewage from the house to the public sewer or septic tank. Again, that means fewer clogs and backups.
Another advantage of plastic sewer pipes is their cost. They are the cheapest sewer pipes, which is good for your bottom line.
Regarding installation, plastic pipes are very easy and quick to install. They are easy to cut and lightweight, which also reduces the total cost of sewer line replacement. This makes it a favorite for DIY enthusiasts.
PVC and ABS sewer pipes are also very versatile. You can use them alone or in combination with other pipes, such as cast iron or clay sewer pipes.
And that's it when it comes to the types and materials of sewer pipes. However, I would like to mention that sewer line repairs and replacement is a job best left to professionals.
The cost of repairing sewer lines is quite high, but DIYers can make problems worse at first, so you should work with professionals. Plumbers also know all the plumbing codes and the last thing you want to do is go against the building codes in your area.
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