What Is A Riser In Plumbing?

Last Updated On March 1, 2024

Updated on March 17, 2023

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what is a riser in plumbing

A plumbing riser is any vertical pipe that carries water from a lower level to a higher level. It is used to bring water to fixtures such as toilets, sinks, and showers, that are on higher floors.  

Think of plumbing risers as vertical connectors, linking one floor with another. In this way your water supply is carried to all floors of your home.

In this blog post, we will discuss what vertical risers are, and why you need them. We will cover:

  • What you need to know about risers in plumbing systems
  • Situations that require additional plumbing equipment
  • Signs you might need riser repair
  • Different types of risers found in commercial buildings
  • Building code requirements for plumbing risers

What's In This Guide?

      What You Need to Know About Risers in Plumbing Systems

      Your plumbing system starts at the lowest level of your home, possibly a basement or crawlspace. Then the water needs to be carried up to the first floor. This is done by installing vertical pipes, called risers, up to the higher floors.

      So a riser is a vertical pipe typically found in a building’s walls that carries water from a supply line to a higher level, such as going from the first floor to a second floor bathroom.

      Riser pipes can be made from either plastic or metal. Metal pipe, especially copper pipe, tends to last longer than PEX pipe or PVC pipe, especially when transporting hot water from your water heater. However, plastic pipe offers more flexibility and a lower price.

      Risers typically contain backflow preventers that prevent water from moving in the wrong direction, preventing water contamination. They may also include a water hammer arrestor to ensure proper airflow.

      Situations That Require Additional Plumbing Equipment

      There are situations where the water pressure is not sufficient to push the water up to the higher floors. This is found in homes on well water, but can sometimes be found in structures using city water.  

      When water pressure is not adequate to push water up to higher levels, the plumbing system requires a pump and gravity tank that work in conjunction with a riser. The pump allows for the water to be pumped up the riser, where it will be stored in an overhead tank.

      Just like a village water tower, gravity pulls on the water in the tank which provides the pressure for all your plumbing fixtures below the tank.

      In these situations, a riser should run directly to an overhead tank. This way, the pump will only run as the tank needs refilling. This will save you money on your electrical bill.  

      Did You Know? Copper pipe is the preferred material for plumbing risers despite its high price tag due to its strength, and longevity, especially for safety-related dry risers that provide water in the case of a fire. 

      did you know what is a riser in plumbing

      Signs You Might Need Riser Repair

      Risers may require replacement after a number of years, just like any other plumbing pipe. 

      Signs that you require riser replacement include:

      • High water bills – which might indicate you have a leak in one of your risers.
      • Wet patches in the wall – which indicate water leaking from a riser.
      • Low water pressure on higher floors – might indicate a problem with a riser.

      If you have a leak, you may be able to fix it yourself if you have access to the pipe. As risers are typically found behind walls, this can make for a difficult DYI.

      Slab leaks located under the concrete slab are even more difficult. If you need to replace a leaking pipe in this location, you will often need to enlist the services of a professional plumber.

      Different Types of Risers Found in Commercial Buildings

      There are different types of risers used in commercial buildings. These would usually not be found in residential houses but might be found in multi-story structures like apartment buildings. 

      A dry riser is a riser specifically designed for fire fighting purposes in buildings 60 ft. tall and higher. It will have a street-level access point generally protected in a steel or otherwise durable box and a glazed door. It doesn’t handle daily plumbing functions, meaning it’s dry most of the time.

      A wet riser constantly transports water from a pump or a tank in buildings 200 ft. and taller. Wet risers require more maintenance than dry risers since they get significantly more use.

      Most homeowners would not have any of these systems, unless there is a sprinkler system installed in the home.

      Building Code Requirements For Plumbing Risers

      There are certain codes that must be followed when designing and installing risers. These codes are in place to ensure the safety and functionality of your home and the entire plumbing system, not just the risers. 

      Plumbing systems – which include risers – must meet local codes in both material and installation according to strict specifications regarding size, angle, and other considerations. Do not attempt to install or replace plumbing risers yourself. Only licensed plumbers can apply for the permit.

      To learn more about these codes, we recommend consulting with a professional plumber or contractor. You can also contact your local government office, where they will direct you to the building department.

      When replacing your plumbing system, your plumbing contractor will create a riser diagram early in the construction stage so that they can plan the most efficient system possible. Risers typically use a  minimum pipe size of ¾”, but plumbers may use larger pipes depending on the number of fixtures involved.

      Frequently Asked Questions Regarding Plumbing Risers

      What is a riser in a water system?

      A riser in a water system refers to a vertical pipe that transports water from a lower to a higher level. For example, a vertical pipe that runs from the basement up to your first floor.

      When do I need a riser?

      You need risers whenever you need water to reach a higher floor. These pipes will connect the lower level plumbing system with the upper floors.

      What are the types of risers?

      The main difference between types of risers are the materials used, such as PVC or copper, and the specific need for the riser.

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      About Plumbing Navigator

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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