Pin Holes in Buried Copper

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by theestimator1, Nov 21, 2008.

  1. theestimator1

    theestimator1 New Member

    I plan to replace a 150ft long Yard Service with type K copper, but I worry about Pin Holes.

    Two of my neighbors had a section of type L copper develop pin holes in their open basements when it was about 10 yrs old. We have treated water.

    If Pin Holes develop in open basements, why wouldn’t Pin Holes develop in copper installed underground ?

    maybe I just worry too much.

    Master Electrician
    Last edited: Nov 21, 2008
  2. Gary Slusser

    Gary Slusser That's all folks!

    It can.

    IMO, the best choice of material is PE (polyethylene) pipe. You can buy it in rolls from 100-500'. It costs less, is easier to use and nothing in water can harm it and it is inert. It comes in ratings of 75, 100, 125, 160 and 200 psi. I wouldn't use less than 160. It is the favorite of most water companies and has been around since the 1960s and used in many residential and small commercial water wells. If your present water line is used for the building ground you will have to add a grounding rod or two.
  3. Redwood

    Redwood Master Plumber

    I would consider black polyethylene to be an excellent choice especially with aggresive water conditions.

  4. Now that you've started a new thread, AND divulging that your area has problems with pinholing,

    That would be aggressive water, ph too high, too low. The water eating the pipe from the inside out.

    So, since this is the issue, I'm calling you out on your skills as a Master Electrician to find out some really important issue to pinholing and copper pipes.

    I'm in an area where copper is king, very rare to hear of pinholing in copper pipe.

    But over the years there's been some issues relating to this, and I've been told that a loose neutral or low grade current travelling through the lines will cause just this.

    Codes in my state require dielectric fittings at the water heater and that controls the rapid breakdown of the water heater itself.

    But every once in awhile I'll find a small section of copper for no reason just cancer out,

    sometimes it'll start from the main on the cold and travel to the water heater, then stop. Cold only, ground wire attached to the main line.

    Care to explain where the logic is in all this, the specific termage so I can relay this information to my customer......because when there's pinholing in my area, it never attacks the entire potable water supply. It seems to only target certain locations and that's why I cannot simply determine the true reason for it happening.

    You could blame the piping.....but why would the cold side, or hot side for that matter be selectively corroding/pinholing when you know the piping was pulled from a large bundle when installed?

    There's something to be said about impurities in the piping, but I'd like to know the close association of electrical systems and the water supply lines in a home where the electrical panel is commonly grounded to the potable water supply.

    I'm no electrician but I believe they've abolished this practice in ky? I thought it was required to now drive two ground rods 10' apart in direct proximity of the panel.

    My last customer had this problem, couldn't get the electrician who wired the house to come out and explain the possibility.
  5. Cass

    Cass Plumber

    Ditto...I am interested also...
  6. Here's another electrical question

    I have a customer right down the street that I've done drain cleaning work for.

    If I plug my Spartan 81 into his outlet on his table where his woodshop is, and I take my cable and attempt to clear his copper/brass drain line,

    sparks fly everywhere, in a bad way.

    My machine has a ground, no GFCI which is soon to change real soon.

    The old man states for the record that he's never had a problem down there ever, blamed my machine.

    Now, I've rodded many drains, including copper ones without sparks flying all over the place.

    When I moved the plug over to the washing machine, problem solved no sparks just like all the other drains I rod.

    What was causing this to happen because I don't believe my machine was to blame at all.

    No way.

    Something electrical in that home was all messed up.

  7. Rugged ---just ask the master.....

    Rugged, you simply should have just asked me.......

    anytime you are stumped,

    all you got to do is ask.....LOL

    also read #5 on my site if you want to see
    why copper pipes thin out
    at the outgoing line from the home and eat up waterheaters so fast.....

    as you can see on my site,
    the system is constantly trying to
    fine a way to ground itself

    If you have any other questions, ....
    please allow me to enlighten you...LOL

    next time you have a customer that asks this question
    send them to my F>A>Q on my site..........

    ( is am sorry RUGGED , I could not help myself LOL)
    Last edited: Nov 22, 2008
  8. theestimator1

    theestimator1 New Member

    Aaah grounding, the most confusing and most misinterpreted subject in the electrical field. You can get a different answer from half of the electricians you talk to. Code Instructors can get stumped and I met one Instructor/contractor who grounded a service for a bldg completely wrong.

    Improper grounding anywhere can create currents on a grounding system and anything connected to it. A neutral wire touching a ground wire anywhere (other than the main service panel) can cause ground currents. Grounding problems can originate in plugged-in appliances, receptacles, subpanels, main service panels, anywhere.

    I have only witnessed one (electrolysis?) pinhole problem at the Naval Academy. The entire length of a pipe that supplied heating water (not potable) throughout a townhouse had pinholes. Can’t remember if it was both supply & return or just supply. I improved the grounding to the electrical services, but I suspected an internal electrical problem with boilers or circulators. This was happening in 2 out of 8 sets of townhomes. Unfortunately, I never found the problem because they demolished the bldgs a little while later.

    To cure a possible electrical problem in piping, I would:
    … Ensure that all ground wires, neutral wires and the enclosure of the main service panel are connected together with a bonding screw or jumper, code requirement.
    … Ensure that all ground wires and neutral wires downstream from the main service panel are not touching, code requirement. Problems within appliances, receptacles, lights, subpanels etc. Good luck with this one!
    … Ensure that a properly sized water ground (bare CU or AL #6, 4, 2 etc.) connects the bonded neutral bar in the main service panel to the cold piping, the hot piping and any other sections of piping that have a problem.
    … Look for supplemental or improperly connected ground rods.
    No guarantees with this procedure because I have never had to do it and it’s like shooting in the dark. If the problem continues after all that, I would call in the Electrical Engineers.

    With loose neutrals and loose hot wires, I’d be more concerned with burning and fires than pinholes.

    I always wondered if bad anodes in water heaters were a major cause of pinholing.

    Most people, including electricians don’t realize that the purpose of a ground rod is to try to bleed off lightning and high voltage from other electric systems during accidents. I’ve never seen this happen, but I’d be surprised if a residential ground rod could carry a huge high voltage current without exploding. There’s a story about Ben Franklin, not the kite story. He determined the size of a wire needed to conduct lightning to earth. Something about the wire had to be no thicker than some type of rod they used in his hay day.

    so as Forest Gump would say,
    And That’s All I Have To Say About That…. just kidding.

    Hope this helps.
    Thanks for everyone’s input,

    X Electrical Planner/Estimator
    Last edited: Nov 22, 2008
  9. theestimator1

    theestimator1 New Member


    Sounds like that receptacle has the hot wire connected to the ground terminal. Needs to be tested to verify, but that’s DEADLY. You could have become fertilizer very easily. Might not be a bad idea to use leather gloves as well as a GFI. I hope that homeowner gets it fixed before someone else . . . . .
  10. burleymike

    burleymike New Member

    This thread reminds me of this video I saw on you tube. I wonder how the electric service of the sparking house was grounded. My house was not grounded at all when I bought it.

    One of the first things I did was new 200 AMP service, then new sub panel. The inspector was not surprised that the original service was not grounded.
  11. Gary Slusser

    Gary Slusser That's all folks!

    Other causes of pinholes are high DO (dissolved oxygen) and CO2 content along with chlorides, sulfates and bacteria. Bacteria produce acidic waste under encrustations which eats through the copper.

    I have seen pinholes develop in new L copper in as little as 2-2.5 years, three water damage leaks over about 5 months. I and an electrician could not find the cause but I'm not sure the electrician believed me about a bad ground on the water heater etc.. My customer had a softener and a UV light for Coliform bacteria. Back then, late 1980s, I did not know about bacteria causing pin holes. I have no idea if it was bacteria, I didn't get back to the customer after he suggested the cause may have been the softened water and I assured him it couldn't be. He was an attorney and i didn't want anymore to do with the problem or the cause.
  12. theestimator1

    theestimator1 New Member


    cool video. no grounding in the world could prevent that.

  13. theestimator1

    theestimator1 New Member

    Gary, Redwood & Rugged,

    Thanks for the advice.
    This site is filled with expert knowledge.

    Now if you'll excuse me, I have to go wipe my nose.

    Last edited: Nov 23, 2008
  14. Gary .....on the subject of soft water......

    All kidding aside... what is your opinion here......

    Gary....most of the troubles I have ever had with water heaters
    leaking at only two years old have almost always had a water softener involved in the system..

    is their something about the salination in the water and any kind of current in the system that cannot ground itself properly that makes the water heater tank become something like a giant battery or electrical ground, eating them alive over a short period???

    here is a pic of a leaking 2 year old brad white..
    if you look close, you can see that the copper ground is on the soft side of the
    system and their is a PRV valve behind the softener that breaks the ground to
    the city water system..

    the ground was moved by an electrician to under the prv valve ....
    but he did not believe me

    So did this soft water heater and the copper somehow become a
    glorfied battery or electrical conductor???..


    Last edited: Nov 23, 2008
  15. Gary Slusser

    Gary Slusser That's all folks!

    All I can say it that all the potential causes of pin holes would have to be tested for and checked and then anything found would have to be corrected.

    Water companies and water heater manufacturers want hardness caused scale to layer the pipe and tanks to protect the materials from the water. That's like treating the symptom rather than the cause. All tank type heaters have a glass lining that's supposed to provide that protection and, the water companies back in the late 1980s convinced the to reduce the acceptable range for pH from 6.9-8.5 to more acidic 6.5-8.5. And now we have many more pin hole problems than before. The EPA then in 1990 or 91 when the Lead and Copper Rules were introduced, they allowed the water companies to not test new residential construction using copper for the first 5 yrs..

    Softening water with a water softener does not make the water more aggressive or corrosive. But people using the Langlier Index, which should not be used, say it does. That index was invented to determine if cement distribution water lines would be dissolved by water. It has nothing to do with metals.

    In your picture, there is a brass by pass valve on the softener that electrically provides conductivity between the inlet and outlet copper pipe. So there is no break.
  16. Thanks for the reply

    Gary....Thanks for the reply...

    actually the prv valve behind the water softener has a union on it,,,,
    which to me , seems to make it a bad connection...

    and what I have found is the current takes the path of least resistance to make a ground...

    it would rather ground iteslf into the heater than
    pass through the brass in the softener and then somehow
    jump across that union

    this still does not answer why most of my failures are with
    water softeners in the system

    so does salinated water conduct electricity with an anode rod hanging down in it???

    or does this somehow increase the electralysis in the tank 1000%??.

    any other ideas here???
    Last edited: Nov 23, 2008
  17. Gary Slusser

    Gary Slusser That's all folks!

    The conductivity of water is measured by the TDS (total dissolved solids), they are why water conducts electricity. Without TDS, water is a rather good insulator. That's why some waters require the addition of salt to get a certain type of humidifier to put out steam.

    Ion exchange softeners usually don't change (raise) the TDS of the water and if it does, it is not by much. The reason the TDS would be changed at all is due to the added sodium in the water.

    All waters contain some sodium, look at labels on bottled water or the water company's water quality report they are required by federal law to send all customers annually. You can find the report on their web sites too. Along with the TDS of their water.

    Having a softener where a water heater fails is probably more of a coincidence than anything else but, if the water is say 4-5 gpg or harder, the heater will fail because of scale build up anyway but, the fuel cost to operate it will be much more expensive than having a softener.

    The best way to protect a water heater is to make sure there is no hardness in the water, the ground is good and the anode rod is good.

    Draining and flushing a water heater is not going to remove anywhere near all the scale in most of them but especially gas and oil fired; it sticks to the inside and bottom. Some electric types will sometimes have some pieces of scale that has fallen off the elements, but due to the drain valve height off the bottom, you can't get all the pieces out.
  18. thanks for the info

    I guess it is just the nature of the beast.

    unknown and almost mystical reasons for these
    units to simply corrode so quickly...

    every house is different,
    the systems have been installed at different
    times and by different people...

    water pressures vary and hardness varies too....

    of course all this corrosion and scale keeps me in

    the water heater and water softener business,

    so I guess I should not complain ,

    or even attempt to solve the problem.

    for that
  19. Gary Slusser

    Gary Slusser That's all folks!

    If the glass lining of the tank is compromised, nothing will prevent the tank from rusting out, and higher water pressure will locate the leak sooner than lower pressure will. lol.
  20. MavisPlace

    MavisPlace New Member

    I'm replacing all the rolled copper water under slab water lines for my house with overhead type L, as the hot water line to the kitchen sprung a leak under the family room and provided supplemental radiant heat. Unfortunately all this additional heat came in the middle of summer. Worked great, but it was costly with the water I was wasting and the strain it was putting on my little a/c unit. I never even opened up the slab because it is in good condition and I did not want to disturb it. Besides, I didn't want to fix one section of pipe only to have it spring a leak 10' downstream. Anyway, when I researched the problem for houses built in my area (Northern California), the consensus was that the soft rolled copper was often dented prior to or during the pour, and this indentation in the wall of the pipe eventually wears through, even without particularly hard water running through it. I haven't read that cause being mentioned here, though the grounding issues that have been discussed are very interesting.

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