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Community and Q&A

Water pipes going underground from water heater to faucet?

fedepfel | Posted in Energy Efficiency and Durability on

Hello everyone and happy last day of 2013,
I am in Atlanta, Zone 4, and in the process of building a house that will be as efficient as possible. My contractor just explained to me that the hot and cold water pipes coming out of the water heater will be running underground for about 50 feet before they re-enter the house envelope and reach the shower. I am not a pro but i am very concerned that i if this is not fixed i will paying my bills to have the ground heated. Am i right?

Can anyone offer some advice on this?



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  1. GBA Editor
    Martin Holladay | | #1

    The most important principal of designing an efficient hot water distribution system is to locate your water heater near your hot water faucets. You might consider serving the hot water needs of your shower with a tankless gas water heater or a tankless electric water heater located close to the shower.

    For more information, see the following articles:

    Inefficient Hot Water Piping Layouts Waste Hot Water

    Waiting for Hot Water

    All About Water Heaters

    Efficient Plumbing Supply Layouts

    Point-of-Use Electric Tankless Water Heaters

  2. KeithH | | #2

    Is there something unusual about your building site that requires your water heater to be so distant from your point of use?

    If not, I'd say fix this design flaw now. If there is some site issue, please share it. Is there a subcontracted plumber or did the builder come up with this terrible idea all by himself?

    Are you using a conventional tanked water heater, a power vent, or a tankless? Gas or electric?

  3. fedepfel | | #3

    Thank you for your answer!
    i am actually considering either tankless or two smaller systems, but what about running the hot water lines underground? is that efficient?

  4. fedepfel | | #4

    Hi Keith,
    thanks for your answer. No, there is nothing unusual about the site. it's a slab on grade and the builder run the lines under the slab, but i am thinking that this can be solved by running the hot water line within the house envelope.

  5. GBA Editor
    Martin Holladay | | #5

    It's possible to insulate buried water lines, but I don't recommend it. Even if the tubing is well insulated, the hot water line is much too long.

    You don't want to locate your water heater 50 feet away from your shower. The articles which I suggested you read explain why.

  6. davidmeiland | | #6

    I agree, move the water heater much closer to the point of use, and/or add another unit. Keeping the hot water piping very short is key to saving water and energy, and avoiding long wait times at the fixture. Running the piping under the slab is not in itself a big problem, IMO. In a slab-on-grade house, sometimes the most direct run to the fixture is under the slab. Obviously you have to look at each case separately, but I would probably rather have a short run under a slab than a long run drilled through the framing all the way around the room.

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