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Recurring Copper Pipe Corrosion in Underground Water Main

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  • Recurring Copper Pipe Corrosion in Underground Water Main

    Hello Experts. I need a miracle!

    I moved into a new construction home and after 4 years developed a seeping leak in the basement which was caused by a severe pitting and corrosion of the underground copper water main pipe. Picture below shows what the relatively new copper looked like. All the non-buried copper in the basement is 100% fine. Only the underground copper was corroded. Spent a small fortune to excavate and put in a new copper main line. 18 months later, I am now in the same situation. I do not believe it is soil conditions or water issues because no neighbors have similar problems. I live in a basic suburb, no factories or abnormal interferences. The effected area was filled with sand after we replaced the first time, so it's unlikely it is soil conditions.

    An electrician tested the copper pipe for stray voltage thinking it could be some sort of electrolysis corrosion but did not detect anything. I’m at a loss and living without water. I need to redo the line again with copper because my town will not allow anything else. But I need to find the root cause before I rip and replace again. The DPW has not seen similar issues in my town. I've also attached pictures of my grounding, which electricians have also said is fine. The town will allow me to sleeve the copper in PVC this time, but I do not think this will help if it's electrolysis related. I wish I could use pex, but that will not be allowed by the town. To me, it seems like some stray voltage is hitting the copper somehow. But no electricians seem to be able to find it, or are not looking for it in the right way perhaps. Perhaps related, our 5 year old hot water heater failed (leaky bottom) a couple months ago too.

    Does anyone have any suggestions or experience with this?

    Thank you.

  • #2
    Copper should not have any contact with cement because it will corrode, should of run the line through a sleeve.... same thing in our state regarding ( new or newer ) oil lines for your heating boiler when it's buried in cement needs to run through a sleeve usually plastic. .

    Comment


    • #3
      Definitely sleeve it or wrap the entire line in 2 layers of 10 mil tape. Slide it through over piping or HDPE .

      Something in the soil is eating the copper.

      Rick
      phoebe it is

      Comment


      • #4
        Thank you. I did read about how some states are now requiring the copper to be sleeved when it goes through cement. Although the builder has built dozens of houses in my town and hasn't sleeved through cement (yet we are the only ones w/ the issue). After reading this I'm not so sure that is it: https://www.copper.org/applications/..._concrete.html

        There isn't much copper through the concrete, yet the corrision continues for many feet past that.
        Last edited by bluearchtop; 01-02-2020, 09:14 AM.

        Comment


        • drainman scott
          drainman scott commented
          Editing a comment
          I was thinking thermal expansion stress ...... below Pebs pasted a good article about other contributing factors ( soil conditions--- electrolysis ) worth a read.

      • #5
        https://www.copper.org/resources/pro...derground.html

        Hi
        Just a thought, does the copper run along by any other pipes in the ground

        Comment


        • #6
          You only show part of the grounding and bonding. I see a bond across the two meters and a conductor (black wire) that goes somewhere out of the picture supposedly to tie in with your house ground, but nothing more.

          Show us the grounding at the main panel and the ground rod(s). IF your water line is being used as the house ground that is not good. I am not an electrician but I believe there should be at minimum one 5/8" x 8 foot copper clad ground rod driven outside near the main panel if the panel is in the house or at the panel if outside. Your phone and TV cable should be bonded to the house ground if you have these which most homes do. If you have solar panels that system must be properly grounded and bonded with the house ground. If you have separate grounding systems with different potential to ground (differences in their ground resistance readings) because they are not bonded together there WILL be current flowing between them. It might be so slight (mA or even uA) that your electrician is not using a meter sensitive enough to detect it.
          Last edited by Bob D.; 01-02-2020, 11:12 AM.
          "It's a table saw, do you know where your fingers are?" Bob D. 2006

          https://www.youtube.com/user/PowerToolInstitute

          https://www.youtube.com/channel/UC1p...qcZKHyrqKhikFA

          ----

          Comment


          • toolaholic
            toolaholic commented
            Editing a comment
            To drive the copper ground rod, a large Roto hammer or Jack Hammer make it EZ. Good luck SULL Another M*******

        • #7
          Thanks. Yes, the black wire goes to the panel on the left. And then on the service outside, there is a pipe that goes to the ground which should be our earth grounding. I'm unsure of the bonding. Waiting on an electrician to confirm that.

          Comment


          • #8
            I think the culprit is probably the ground, Since our pipe are no longer copper for the last 20-30 years but a rebranded kitec name and there are no ground wire on it. The panel has to be grounded on it's own. All the old houses have copper in direct contact with concrete and I haven't seen it corroded. I would tell the electrician to ground the wires somewhere else and not ground it on the copper pipes!

            Comment


            • #9
              I was able to get our town to approve the use of HDPE instead of copper. Our town's electrical inspector says he does not recommend using grounding rods instead of the copper grounding. He said because we have an inground pool in the back yard it's not recommended. Right now we have one ground rod and one grounding to the copper. We'd have to get 2 ground rods to be to code if we drop the copper. Is it true that the grounding could possibly have some risks w/o the copper? Thanks.

              Comment


              • #10
                Originally posted by Pro Service View Post
                I think the culprit is probably the ground, Since our pipe are no longer copper for the last 20-30 years but a rebranded kitec name and there are no ground wire on it. The panel has to be grounded on it's own. All the old houses have copper in direct contact with concrete and I haven't seen it corroded. I would tell the electrician to ground the wires somewhere else and not ground it on the copper pipes!
                Current code requires the main grounding electrode is a ground rod or in many cases 2 ground rods. All rods must be bonded together and bonded to metallic piping systems, water and gas.

                Comment


                • drainman scott
                  drainman scott commented
                  Editing a comment
                  NEC article 250 also states that bonded metallic pipe must be in direct contact with soil 10' so wrapping or sleeving the entire pipe would be a code violation Y/N ?
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