What Is A Riser In Plumbing? [Meaning, What Happens If Damaged, & How To Tell]

Blog, Construction, Plumbing

If you’ve ever wondered what a riser is in plumbing, you are not alone. We’ve all seen some upward-connected pipes at commercial buildings without knowing what they do. Basically, a riser, also termed a riser main, is a pipeline charged with moving water from one floor to another. It helps solve plumbers’ significant challenge: carrying water from a lower floor upward to another floor.

To help you understand better, I will explain further what a riser is in plumbing in this article. I will also write about what they are made of, their lifespan, and signs to determine if the riser for your building needs to be changed.

What is a riser in plumbing?

A riser is a vertically connected water supply line that allows water to run from a lower floor to an upper floor. In other words, it moves freshwater against gravity to the upper floors of a building. A riser has a feature known as a backflow preventer, which stops or prevents water from moving in the wrong direction.

What are risers made of, and what is their lifespan?

Risers can be made of a variety of materials, and each of these materials has its own estimated lifespan. They include;

  • Plastic risers: Made of plastic and has a lifespan of about 30 – 40 years
  • Copper risers: Made of copper and has a lifespan of about 100 years
  • Brass risers: Made of brass and has a lifespan of about 70 years
  • Galvanized steel: Made of galvanized steel and has a lifespan of about 50 years

Note that the level of usage can also extend or shorten the lifespan. The presence of chemicals that can cause corrosion may also lower their lifespans. Maintenance history also plays another huge role in how long risers last.

What happens when risers are not maintained?

Failing to maintain the building risers can be disastrous. Not only do you put the safety of others at risk, but you will also automatically spend even more eventually. There is the cost of replacing any wall, flooring, or ceiling damaged in the process. Add the loss of revenue that may occur while business is interrupted or your tenants have to relocate temporarily.

Not maintaining your risers is like having a ticking time bomb in the building. To avoid this, ensure a visual test is done annually to confirm its durability. There are also common signs to tell if the risers in your building need maintenance or replacement. I will highlight them in the next section.

How to tell if you need a plumbing riser maintenance or replacement

Specific signs indicate that your building’s risers need maintenance or replacement. However, most engineers at this point will advise you to replace instead of repair. This is because, at this point, repairing may be a temporary fix only.

Some of the potential signs that your building needs replacement risers are;

1. Gradual water pressure decline

If the building’s water pressure drops, with the upper floor experiencing the worst pressure, then the risers are faulty. They could be decaying or blocked.

2. Discoloration

Once the risers wear out, they may cause holes and leaks in the pipeline. The obvious sign of this is discoloration of the water.

3. Signs of leaks on the walls, floor, or ceiling

Depending on how the building was designed, you could notice signs of leakage on the walls, floor, or ceiling. When you spot water stains on a wall, ceiling, or floor, it means a riser behind or under it is leaking.

4. High water bill

Once you start having a higher water bill for no apparent reason, you can look at the riser pipes for more insight. There could be a leak somewhere, meaning you are being charged for water you are not using.

5. Extremely hot shower

Having an abnormally hot shower is also an indicator that the building’s riser is bad. The cold water is probably traveling through the riser pipe slowly while the hot water travels normally. The result, however, is an abnormally hot shower.


How long do risers last?

The lifespan of a riser is between 30 and 100 years, depending on the material. However, other factors, such as usage level, may shorten or extend this time frame.

How much does it cost to replace risers in a building?

Depending on the building size or the number of upper levels, it can cost hundreds to thousands of dollars. But basically, most contractors will charge $40 – $90 per foot to replace damaged risers.


In plumbing, risers are vertical pipes carrying water from the lower to the upper floor. They are essential in the plumbing of commercial buildings or multi-story buildings. They must be inspected on a yearly basis, as having faulty risers can be hazardous. This article highlights some specific signs indicating that the risers in your building are faulty.

Stay safe. Before you go, do check out Samkinsconstruction for more articles you will find helpful.

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