• Backflow Preventers: Questions & Answers


    Backflow preventers help ensure safe drinking water to a building. Here are common questions and straightforward answers that will help you keep people and the water to a building safe.

    What is a backflow preventer?

    It is a device in the drinking water piping that prevents backwards flowing of contaminated water (e. g. fire sprinklers or irrigation) into the drinking water supply. People could get severely sick if contaminants were allowed to flow into drinking water. Backflow preventers help ensure a safe drinking water supply.

    How can backflow happen and when?

    Backflow is water moving in the opposite direction of its intended flow. This happens because of a change in pressures within the piping systems. For example, a sudden surge in pressure, when a fire pump starts, could cause a backflow. Backflow preventers are needed to keep that from happening.

    Does NFPA standards or plumbing codes reference backflow preventers? And if so, what is the code?

    Although NFPA 25 requires periodic testing and maintenance of backflow preventers, NFPA 13 does not require them to be installed. Many local plumbing codes require backflow preventers to be installed, inspected, and maintained. Some locations also have environmental protection regulations for backflow preventers. The model plumbing codes, International Plumbing Code (IPC) and Uniform Plumbing Code (UPC), contain these requirements and are adopted as or inserted into state and local codes.

    How often do backflow preventers need to be inspected?

    They get tested and inspected when they are initially installed and inspected annually, thereafter.

    When a technician goes to a customer’s location, where can the backflow preventers be found?

    In the south, backflow preventers are typically outside and above ground. In the north they must be protected from freezing and, therefore, could be inside of the building. In all cases, they are downstream of the water meter. Trouble finding the water meter…check with the local waterworks department.

    What are the reasons a backflow preventer could fail the annual inspection?

    Inspection of backflow preventers is required annually. Backflow preventers in fire sprinkler systems may fail due to dirt and debris. For other backflow preventers, parts (such as o-rings) fail over time, due to normal usage (wear and tear).

    Does a technician need a certification and special tools or to perform a backflow inspection?

    Most states require technicians to have a license to install, inspect, test, and maintain this equipment. Some states require a licensed plumber with a special cross-connection certification to do the work. While others allow only licensed sprinkler fitters to work on the backflow preventers in fire sprinkler systems. Most often, common tools, like wrenches, screwdrivers, and pliers are all that is needed, but the training that a technician receives will identify any additional tools that are needed for certain tasks.

    After a technician does a backflow inspection, how long does the inspection ensure the backflow preventer will work properly?

    The inspection only verifies the backflow preventer has been inspected, according to code. Although it verifies things are working properly and no leakage at the time of inspection, nothing is guaranteed for any period of time. That is why it is important that the inspection be done annually, according to code.

    By installing and maintaining backflow preventers to code, building owners can be reasonably assured that contaminants remain isolated from the drinking water, and building occupants remain safe.

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    Disclaimer: The opinions expressed in the above Tech Series article are the author’s only and provide limited information. Although the information is believed to be reliable, Brooks Equipment Company, LLC expressly disclaims any warranty with respect to the information and any liability for errors or omissions. The user of this article or the product(s) is responsible for verifying the information’s accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.