How Does Plumbing Work in an Apartment Building?


Most places need plumbing. That’s a fact in our modern world. However, plumbers can tell you that not plumbing works the same way. Depending on where you live, you can bet the plumbing will differ from one another.

In which case, how does plumbing at an apartment building work? With so many people living in one building, it can make you wonder how the plumbing system works.

If you live in an apartment, it would be pertinent to know how the plumbing in your apartment works. After all, if any plumbing issues occur, you will know what you can and cannot do to fix them.

Types of Apartment Buildings & Plumbing

Not all apartment buildings are structured the same way. Therefore, their plumbing systems are different as well. Depending on the construction of the apartment building, it can either be considered multi-story dwellings or multiple dwellings.

Yet, what makes these two different enough to have different plumbing systems? That comes with identifying and defining these apartment buildings.

Multi-Story Dwellings

You can best identify multi-story dwellings as apartments where you have to share the floor with other apartments. These apartment buildings are usually taller and have around five to eight floors, but they can have more. Think high-rise apartment buildings. Since they’re taller buildings, they require greater water pressure to keep running water for each unit.

By needing greater water pressure, multi-story dwellings aren’t sufficiently served by the municipal water supply since it’s too limited. Therefore, its plumbing system has to branch out further so more plumbing fixtures (such as a sink, toilet, faucet, etc.) can get enough water. When you need to accommodate numerous people living in an upwards structure, it’s required to have proper drainage, sewage, and venting systems.

Multiple Dwellings

Multiple dwellings have separate units like multi-story apartment buildings, but that’s where their similarities end. These apartment buildings aren’t too tall. Since they’re not very tall, they don’t need extensive water pressure. As a result, their plumbing system is similar to a house’s plumbing system.

Like a house, the water in multiple dwellings can come from the municipal supply. Furthermore, a system of pipes, faucets, and valves makes sure water gets where it’s needed. You can expect hot and cold water lines that will supply water to kitchen and bathroom faucets. In addition, they can handle dishwashers, disposers, ice makers, and other appliances.

Regarding wastewater, multiple dwellings use a drain-waste-vent (DWV) system to carry it out of each unit in the apartment building. You can expect these pipes to be hidden in the walls, which can be tricky if you run into a plumbing problem in these apartment buildings.

Components of Apartment Building Plumbing Systems

The best way to truly understand apartments’ plumbing systems is to know exactly how they work. Again, whether it’s multi-story or multiple dwellings, it can dictate how these systems are outlined in an apartment building.

For example, multi-story plumbing systems have vertical stacks, horizontal pipes, and branch lines. These vertical stacks ensure no harmful sewage gases are trapped anywhere by providing enough air pressure to be maintained.

Yet, there are different vertical stacks with various uses, such as:

  • Leaders Vertical Stacks: Carries rainwater collected on the roof and down to the drainage system below.
  • Soil Vertical Stacks: Are what is connected to the water closet and urinal.
  • Waste Vertical Stacks: Connected to plumbing fixtures that don’t involve human waste.

Considering all this can make it hard to discern what parts of the plumbing system are from your unit or someone else’s. However, the pipes you can see in a unit most likely originate from it.

Alternatively, it’s not strange that two to three apartments can share pipes or a certain section of pipes. For instance, the waste line from multiple apartments may run into a common line for all the apartments. In these cases, a potential clog from your neighbour’s pipes can affect you by causing your plumbing fixtures’ backflow.

There is no real universal plumbing system for apartment buildings. Depending on the structure of the apartment building can dictate how much water pressure is necessary and whether a municipal water supply is enough to provide for numerous units. Some might have pipes strictly within a unit or end up sharing pipes with a neighbouring unit. It’s why knowing what plumbing system you’re dealing with in an apartment building so any plumbing problems don’t adversely affect you or your unit neighbours.