The authoritative public forum
  for Metal Finishing since 1989
  

  -----

New copper pipes degrading in historic home. Water unsafe to drink!

2006

From the first week that we started to use our first floor addition (approx. 1 year ago) I discovered that there was obvious blue water rings around the bath tub and toilets. I had the water tested and the results were unsafe water due to high levels of copper. I also tested the 'old' section of our home to compare and define where the problem was. The old section was 'perfect'. It definitely was from the extension of the new pipes. Our p/h etc was tested and without filtration or chemicals it was nearly perfect. We have a wonderful well water supply.

I have had 'experts' here. First I was told that it just has to clear out and in a few weeks it would be fine. Never did! .Next I was informed that it may have been an installation problem caused by poor flux or improper fluxing of the joints.The installer denied that would be a problem and if it was it would go away shortly.It didn't. I then contacted a metalurgist since the copper supplier would not even return my calls after hearing the problems.The metalurgist said that I should look for improper grounding and that he had found electrolysis could cause deterioration of pipes leading to horrific problems. I then called several electricians.They noticed that there was improper grounding within the panel boxes that were part of a new 400 amp service.I had the builder during construction all overhead lines leading into and on our property placed underground with the meters at on an outbuilding.The metalurgist told the electrician to check the grounds and neutral lines leading to our inside boxes.He found that not only were numerous breakers improperly grounded in the addition which he corrected but the voltages or wattage (I am uncertain) when checked with a device that went around the neutral and ground cables was unsafe and to look for an exterior problem.The house panels were properly grounded however when he went to our outbuilding where the meters were he found that they were grounded also.The metalurgist told the electrician to 'cut' the ground at the outbuilding and 'voila' the readings inside the house now were balanced.The copper levels dropped after testing however we still have degrading and blue resides.I replaced pressure pumps,circulation pumps and the brand new Weil McClain hot water heater at the plumber's suggestion.

We still have a problem.Could it be from the flux?A copper rep told me that he noticed flux traces in the sample lines that we cut out.( I had removed about 50 feet of pipe that was accessible but the majority is behind walls necessitating destroying our gorgeous addition. He also noticed that the inside of the pipes were not reamed leaving a rough edge which according to him is not following code.Please help me out.We are afraid to drink our water and for 18 months drink bottled water.I even have signs at each bowl "DO NOT DRINK CONTAMINATED WATER".

Gene Epstein
consumer - Newtown, Pennsylvania, USA

---

From this distance I would certainly be continuing to investigate the electrical situation rather than flux, burrs on the pipe, metallurgy of the pipe, or anything else. I think your electrician did observe and correct a serious problem of the neutral wire being grounded in multiple places. In view of the fact that you have ground rods, also make sure that no grounding straps of any kind are attached anywhere on the water pipes, since multiple grounds in different places can produce a ground loop current. I think I'd also ask the plumber to install a dielectric union at the outlet of the well pump because something might be going on with that pump wiring which is allowing current into the piping. I'd strongly suspect either electrical leakage from the well pump as the cause, or some potential difference between the old electric system and the new--but if no ground straps are connected to the piping there should be no corrosion regardless.

If you do find any kind of ground straps on the piping, ask the electrician to disconnect them and test the voltage and current from that strap to the pipe. It would give a clue to the source of the problem.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

---

2006

There are many reasons why your water turns blue. The most obvious one is that copper is being dissolved from your copper pipes. The reason for the dissolution could be many reasons.
Firstly, if the plumber who installed the pipework overdid his use of flux on the joints, there will be corrosion; this will be obvious from streaks running from the outside of the joints. If this is the case, the problem may well go away once the flux has been washed off.
The second possibility is that the new copper pipe has been connected to another pipe that is more cathodic than your new pipe; - this will cause corrosion of your new pipe. Older houses, especially in the UK, had lead pipes and whilst they are OK in hard water areas, they are not so good in soft water as they get dissolved. Where pipe polarity is concerned, it is a very complex subject as although, say, copper and iron connected together would make the copper cathodic, under some circumstances it is possible for the iron to be cathodic and therefore make the copper anodic, which is bad news for the copper! This is an unusual situation and will only occur under certain specific conditions, especially if the (say) iron pipes have been treated with some sort of protection process.

The third option depends on whether the corrosion is on the hot or cold water pipe. If it is on the cold water (below 40C), then the problem can be due to what is known as Type 1 pitting. If it is on the hot water (above 60C), it is Type 2 pitting. I know more about Type 1 than 2, do will limit most of my response to Type 1; more information on Type 2 pitting can be found on other websites. The thing about Type 1 pitting is that it occurs on new pipes that have been drawn and heat treated to leave a thin carbon film on the inside of the pipe. If the water composition is of the correct blend, then the carbon film allows pitting to start and a semi permeable membrane is set up, through which corrosion will occur. One geneal trend with Type 1 potting is that is happens with borehole water with a pH of usually between 7 and 8.2. However, for this pitting, the water must be of the correct blend of chloride, sulphate, pH and dissolved oxygen; it is a complex relationship and needs a nomogram to predict the outcome of the mixture. Type 2 pitting is found with hot water is generally associated with soft water. Unfortunately, for some reason I do not understand, there is not much credence given to these types of water corrosion in the USA.

If it is corrosion by pitting, this may be solved by using a sacrificial anode such as aluminium, but talk with your plumber about this, especially since you are using well water.

The final possibility is that the electricity earth system could polarise the pipework and this could cause your problem, but remember, in all corrosion there must be an anode and a cathode, so look for anything that could cause polarisation. If by any chance you find a plastic connector between two pipes, this will have been put in to break the electrical circuit and to get round this problem of polarisation.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

---

Please ask your electrician to see the November issue of EC&M for an article entitled "The Shocking Truth About Grounding Electrode Conductors" which explains how a pipe or other grounding element can carry very large currents undetected if there is an "open neutral" anywhere. The severity of the problem you describe makes me believe that this is not an incident of wrong flux, burrs, or galvanic activity, but a substantial and continuous electrical current. Step 1, measure the current in the hot wire to the well pump, then measure the current in the neutral wire to the pump.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006