Your home’s plumbing, drain and sewer system is more complex than you may realize. If certain parts of the system weren’t designed and installed correctly or are in poor condition, it can lead to major issues like frequent clogs, leaks, sewage backups, etc. In terms of a drain and sewer system, one of the most important components is the plumbing stack. Here, we’ll explain exactly what a plumbing stack is, what purpose it serves and how to spot the signs of potential issues with the stack in your home.
What Is a Plumbing Stack?
The plumbing stack is a large diameter drain pipe that runs vertically from the bottom to the top of the house. This pipe is where most or all of your plumbing fixtures drain into. The drain pipe from each fixture is sloped downward to ensure that everything flows smoothly and properly drains into the stack.
When discussing a plumbing stack, plumbers generally separate it into three different sections. The lowest section, commonly referred to as the soil stack, sticks down the foundation and ties into the house’s sewer line. The middle section is known as the drain stack, and this is the section where all of the drain pipes tie into. The upper section is known as the vent stack, and it extends from above the highest drain in the house and runs up through the attic and out of the roof.
Understanding the Role of the Vent Stack
Each section of the plumbing stack plays a crucial role in allowing you to dispose of waste and wastewater. It ensures that everything flows out of the house and into the municipal sewer system or your septic tank if your house is on a septic system.
It’s fairly easy to understand the role that the drain stack and soil stack serve, as they simply allow the wastewater from your plumbing fixtures to flow downward and out into your sewer line. The vent stack plays a different but equally important role in ensuring everything works properly. In fact, it actually plays two different roles.
One of the roles of the vent stack is that it allows air to get inside your plumbing system whenever you use it. When you shower, flush a toilet, etc., the movement of the water as it flows down the drain and plumbing stack causes air to get pulled in through the vent pipe on the roof. This incoming air plays a critical role in ensuring that the wastewater drains properly.
If you were to seal off the vent pipe so that no air could get in, you’d end up with a vacuum in the drain and sewer system that results in everything draining slowly or potentially not draining at all. The incoming air from the vent pipe ensures this doesn’t happen, allowing everything to flow smoothly out to the sewer main in the street.
The second purpose of the vent stack is that it allows the sewer gases that build up in a plumbing system to escape and get vented outside. If sewer gases couldn’t escape, they could build up in pipes to the point where they may then start to escape by flowing out of various plumbing fixtures.
A high concentration of sewer gases like methane and hydrogen sulfide could even lead to a fire or explosion due to how incredibly flammable they are. Making sure the sewer gases continually get vented outside is also important for protecting everyone’s health, as some of the gases are toxic in high concentrations.
The P-traps underneath your drains are also there to prevent sewer gases from being able to flow out of the drain and into the house. The way a P-trap works is that it has a bend at the bottom that holds water and constantly remains full. The water basically acts like a seal that blocks off the bend, ensuring sewer gases remain trapped in the lower section of drain pipe and can’t escape. This is also where it’s important that air always gets pulled in through the vent stack when you use your plumbing.
If the vent stack were clogged or sealed off, the resulting vacuum would cause air to be drawn in through some of your drains. That means the water would get sucked out of the P-trap of each of those drains, resulting in the sewer gases no longer being trapped and rising out of the drain.
Plumbing Stack Issues to Watch For
Although major plumbing stack issues are luckily quite rare, you could encounter a problem like part of the stack leaking. As with any other pipe, the pipes that make up each section of a plumbing stack can potentially get damaged or start leaking for various other reasons. Leaks can easily occur due to one of the fittings that join two pieces of pipe coming loose over time.
This sort of issue is especially common with old cast iron pipes. If you have an old cast iron plumbing stack, it can also just crack simply because of how brittle cast iron pipes can get over time. Frequently using drain cleaner can also result in the glue that holds PVC pipes together essentially dissolving, resulting in wastewater leaking out of the joint. This is one of the many reasons why you should try to avoid using drain cleaner as much as possible, as it has the potential to do major damage to your plumbing system.
If your plumbing stack is leaking, wastewater will continually pool around the base of the stack on the foundation floor in your basement or crawl space. If you have a basement, you’ll usually notice some fairly obvious signs of water damage on the floors or at the base of any walls near the stack. You’ll almost certainly notice a strong smell of sewage in the nearby area as well.
Fixing a leaky plumbing stack isn’t a simple job, as it almost always requires tearing out sections of one or more walls to access the pipes. Nonetheless, it’s definitely something you want to get fixed as soon as you can due to the risk of the leak causing extensive water damage. Mold growth is also another major concern with this issue or any other type of plumbing leak.
Issues with the vent stack such as it breaking or getting clogged are a bit more common. Clogs can happen just due to debris getting stuck in the vent pipe. Birds or pests like wasps have also been known to nest on top of or inside a vent pipe, resulting in it becoming partially or completely clogged. One of the biggest concerns if your plumbing isn’t properly vented is that it can cause everything to drain slowly.
In fact, solids can get trapped in the sewer line, resulting in it getting clogged and backing up. That’s why it’s important to contact a plumber if all of your drains are slow, as this is a sure sign of an issue with either your sewer line or vent pipe. Some other signs that often indicate there’s an issue with your plumbing vent are air or gas bubbles in a toilet bowl or the water in a toilet occasionally making a burping or bubbling sound.
Contact Us Today
If you need a trustworthy, local plumber in the Indianapolis area, Hope Plumbing, Heating and Cooling is the company to look to. We offer expert repair and installation services and can help you overcome any issues with your vent stack, sewer line or any other part of your plumbing system. We offer plumbing inspections so you can always know what’s going on with your home’s plumbing.
To get expert plumbing services from one of our experts, call us today.
