How Domestic Hot Water Return Piping Save Water?

Michael Tobias
4 Minutes Read
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    If you are looking to have a domestic hot water return system installed, it is likely that you are fed up with having to wait for hot water every time you turn the faucet on. The hot water return systems are proven ways to conserve water. However, it is not the easiest task to find your way through local codes and regulations when it comes to home improvement projects such as the installation of a hot water return piping system. So for those who feel stuck in the minefield of municipal codes, today we will be looking at everything you need to make sure is up to code, when installing domestic hot water return pipes.

    What is Hot Water Return Piping?

    Say you have a tankless water heater or furnace installed in your home. Chances are that every time hot water is needed, a little amount of wastage takes place. This happens because you have to let the cold water run through for a few minutes before hot water is available. Over time, these seemingly small amounts of water can turn into gallons and gallons of wastage annually.

    Essentially, domestic hot water return piping is the modern response to this problem. A domestic hot water return system is installed in order to keep hot water readily available in all hot water faucets. There are two basic elements that make up a domestic hot water plumbing system; return pipes and a re-circulation pump.

    Hot Water Fixture (1)

    Installation of Hot Water Return Piping

    There are three things to consider before undertaking any new installation project. Firstly, why are you installing it? Second, how one would go buy it, and thirdly, what rules and regulations need to be kept in mind, throughout the duration of the project.

    While this article will be exploring all the regulations you must adhere to in the later stages of installation, if you are still in the early stages, remember to carry out a viability analysis, so that you know whether your reasons for opting for return piping check out.

    Also bear in mind that the Chicago Municipal code explicitly states in Article 6, 18.29.601.2, that all installation and alterations of domestic plumbing systems must be inspected by a qualified representative of the Chicago Water Works System.

    Get your hot water return piping installation by licensed professionals.

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    What Type of Pipes Should You Go For?

    The types of pipes are differentiated based on the material they are made a form. The Chicago Department of Administrative Hearings, Rules, and Regulations authorize copper, iron, brass, galvanized steel, and CPVC, however, brass and iron are rarely used for domestic systems these days.

    • Copper (Resists corrosion, rigid and flexible tubing with varying thickness; type M, type L, and Type K)
    • Galvanized Steel (Galvanized Zinc coating on the exterior to protect the pipe from the outside).
    • CPVC (Incredibly durable and lightweight with a lifespan of 50 to 70 years)


    It is impossible to effectively install hot water return pipes without giving thought to the size of the piping and the kind of pump being used. When it comes to returning hot water pipes, sizing can be a little tricky. While Chicago codes explicitly give sizes for most common fixtures, it is important to remember that those values are for incoming pipelines.

    For hot water return pipes, the more general clause of Article 18, 29.604.10.1.2 in the municipal code should apply, which states that pipe sizes should be chosen such that the velocity of water should not exceed 8 feet per second. When a pump is required, velocity should be no more than 5 feet per second, while ensuring the maximum pressure is 100 psi.

    However, the code also limits the water pressure levels at 85 psi, beyond which pipes are at risk of leaking. As a rule of thumb, hot water pipes are also sized a bit smaller than the standard ½ inch cold water pipes simply because they are not under pressure from the main supply.


    Inevitably, installing hot water return pipes will involve some sort of joints. Clause 29.705 of Article 18 in the Chicago municipal code is dedicated to plumbing joints entirely. It contains the essential requirements of how joints must be constructed and the materials that can be used in making them. Remember, have your plumber ensure that all joints are up to code and safety regulations before your hot water return system becomes operational.

    Remember to Hire Licensed Professionals

    As with joints, the clause 29.106 of Article 18 is dedicated solely to permits and licenses. For starters, only a licensed professional is authorized to handle plumbing duties in the city of Chicago. Not hiring a licensed plumber or deciding to go at it on your own may result in a violation of municipal code, resulting safety-related consequences.

    That being said, there are also rules for what constitutes as a licensed professional plumber. In order to provide professional plumbing services for installing or extending your hot water return system, they need to have received formal vocational training or have apprenticed under another professional for a certain number of years.


    Installing a hot water return system is not only a great way to save energy but is also an effective step every homeowner can take towards water conservation. However, considering that water of temperatures up to 150 degrees Fahrenheit will be passing through these pipes, it is best to the have all safety measures in place. That is where local municipal bodies come in. It may feel tedious to have to follow such specific instructions for every little step but in the long run, this will not only benefit the occupants but also ensure the longevity of the plumbing system.

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    Tags : Domestic Hot Water plumbing design Chicago Chicago Plumbing Code Hot water return piping

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