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Ted Mooney, P.E. RET
Pine Beach, NJ

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Copper corrosion and blue water in residential water system

Quickstart:
     Blue water indicates dissolved copper in the water. One theory for its cause is poor water chemistry; the more common theory is that it is an electrical phenomena -- most likely the result of improper grounding. Smarter people than us are confident of one theory over the other. Read on ...

Q. I am a civil engineer trying to figure out the following problem for a high-end home builder. After just finishing this exclusive house, the owner started complaining about blue water in their domestic water system. The local water authority was contacted and confirmed through water sample analysis that it was copper corrosion, and happening only at the referenced house. Suspecting potential electrolysis due to improper grounding of the electric wiring, an independent electrician was hired and confirmed that grounding was correct. Further inspection revealed that the copper piping from the hot water heater was connected to galvanized steel reducers and the connection was corroding and starting to leak. Does that explain the blue/green water in the system? Both the hot and cold water had the coloring, with the cold water having more pronounced evidence of the bluish tint! Due to the size of the house, the hot water heater is part of a forced hot water system to ensure hot water is available instantly at any location in the house. Any explanation for the copper corrosion? Is it electrolysis due to improper electric grounding even though no evidence was found? Is it due to the galvanic corrosion from the water heater? Any ideas?

"The Blue Death"


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A. This is a strange problem, and sounds to me like it is almost surely related to improper grounding of electrical service causing electrolytic dissolution of copper. Can you turn the power off at the main, and run the cold water, to see if it clears up?

Both galvanizing (zinc) and the pipe underlying the galvanized surface (steel) are anodic to copper. These materials go into solution preferentially to copper. Remember the high school chemistry experiment of putting a nail in copper sulphate: the copper deposits on the nail because iron goes into solution to pull the copper out, not vice versa. The very rapid failure of the galvanized joint may well also be due to the electrolytic action from the electrical system.

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

A. Another possibility: Maybe the electrical system is grounded OK, but there is an appliance with a small earth leakage - not a full-blown earth fault that would trip a protection device - and the small earth leakage is causing the corrosion. Certainly sounds as though SOMEWHERE there is a source of electric current through the water pipework.

Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.

A. If you can find someone with a clamp-on Ammeter large enough and sensitive enough, you can check the water supply-pipe for current flow. Sounds like an interesting problem, please let us know what you find.

Tom Gallant
- Long Beach, California

A. Blue Water:
I am a retired electrical inspector of 25 years an electrician for 45 years. When I was an Electrical Inspector I was called to a 48 unit condo that was complaining of blue water staining sinks and tubs. One woman complained of getting blue hair. What I found was an 600 amp service grounded by a 3/0 wire to a 1.5" water line that ran through the building to two cu ground rods outside.

Everything looked good but on further inspection I found a water softener was installed with a plastic manifold cutting off the ground path. The grounding current was showing on water lines everywhere except ground rods. A 3/0 jumper at the water softener corrected the blue water.

I have been retired for 23 years and have recently moved into a condo and was told they have blue water. When checking grounding there was a fluctuating current Up to 4 amps. With an electrical contractor we discovered the original contractor cheated on ground rods; they were only 18" long and just went through concrete protruding 3" two" into the ground ... 10' copper rods were installed.

For single family homes with blue water. It could be the bonding to water lines that are copper from the street. The building ground (ground rods) are not connected. If a water softener was installed with a plastic header (cutting off grounding) ground current can run through water but it causes electrolysis which will produce blue water.

Harold Keating
Retired Elec Inspector. - Regina Sask.
November 18, 2024

Ed. note: Please also see response below from Steven W of Santa Ana, California who feels that this is a water chemistry issue, not an electrical one.

Q. I have a 10 year old home, that has had 5 leaks in the copper water pipes. Always the cold water lines. To make matters worse, the plumbing is run under a concrete slab. 5 different plumbers think there is some sort of electrolysis causing the corrosion of the cold water lines. But, none have any idea how to stop the problem. Evidently, this can be a problem with electric hot water heaters, but ours is gas. You can even feel an electric tingle if you touch a cold water pipe. Any ideas on how to fix this?

Q. I have a similar problem in that I have a .75 inch cold water copper pipe under my slab approx. 20 feet long and there have been 5 separate pin hold leaks in this section over a 6 year period. To my knowledge, there have not been any leaks in the other sections of the house or the hot water pipe. The house is 30 yrs. old. Any suggestions ?

Thanks

Q. 2 years ago I was called to investigate water in a 1st floor ceiling. The house is approx. 25 years old with copper piping. There is a 2nd floor bathroom above the wet ceiling. I investigated and saw no evidence of a fixture leak. We took the ceiling apart and found pin holes in a few locations with green stains nowhere near the sweated joints. The house has city water. My first thought was low pH and would have pursued this if it were a well system. We had a plumbing contractor in to repair the pipes and analyze the situation. They stated it was caused by electrolysis. They proceeded and repaired the pipes that were visible. I explained to the homeowner ( not fully understanding electrolysis) the situation and said we should get an electrician in to look at the bonding, they did so and he said everything was ok. @ years later the customer called me back and said the leak reappeared in the same area. I visited the site and found in the basement near the service panel more pin holes. I have our electrical contractor meeting me next Monday. I need any info on this including possible causes, testing and solutions.

Thank You,

Q. PROBLEM: Corroding pipes and copper precipitate in sink basins (and maybe in the bodies of my family as well).

I live in an old house, built in about 1940. All the pipes were galvanized, but I have been changing them to copper and have isolated the galvanized sections with dielectric unions. We are on a domestic well and our water has pH values that range between 6.1 and 6.9, depending on time of year. I?m not sure what is causing the pH change, but it seems that the lower pH values occur during the summer.

The pump intake is PVC. The piping between the pump and pressure tank is PVC. And, the outlet between the water conditioning tank and the main copper water pipes is PVC.

I installed a water conditioning system to manage the pH. The tank is filled with aluminum hydroxide and calcium carbonate. The water has become harder, but the pH doesn?t seem to be raised to normal (i.e., 6.9 to 7.1) as advertised. The thinking was (by the salesman, that is) that I had a low pH problem and that the copper was dissolving in this low pH environment. Measurements of pH in my well and on the downstream side of the pressure tank and water conditioner are about the same, suggesting that there may be electrolysis occurring further downstream somewhere.

The pipes are corroding on the inside. My plumber (who suggested that I contact an electrical or chemical engineer about this problem) said he rarely sees copper pipes that have become so "eaten away".

QUESTION: What can I do to stop the electrolysis and high copper concentrations in my drinking water?

1) Is there a non-toxic sacrificial metal that could be installed in the plumbing system?

2) Could I connect all plumbing components (pipes, hot water tank, well pump, recirculating pump, Jacuzzi pump, water conditioners, etc.) in the house with a copper wire and ground it to one of the electrical service grounding rods?

3) Is it possible that electrolysis is occurring because of the type of solder that was used in the copper pipes? Some of the copper pipes were installed long before I purchased the home. Is there a different electro-potential between copper and silver solder versus lead solder?

I need help and would sure appreciate any ideas and suggestions.

A. I think your plumber's advice is basically good and that you need to contact an electrician or electrical engineer who is experienced in this. My presumption is that an electric current, possibly a ground loop, is causing this corrosion.

A. Another factor to consider could be microbiological action. This is normally characterized by separate nodules on the inside of the pipe. There are a number of organizations that can test for it. Check out MIC - microbially influenced corrosion. Good luck!

A. Domestic copper pitting occurs randomly with well water and only rarely on municipal water. Low pH, below 6.4 dissolves copper piping, generally through uniform wall loss and pipes last 5-10 years.The serious cause is carbon dioxide. The exact way of corroding is not readilly explainable with carbon dioxide.

Domestic well waters usually are treated with calcite mineral installed in a water softener tank. This method adds hardness to the water and elevates the pH. It is low maintenance and is used frequently. Another method is to install a soda ash liquid feed system and add as needed to get to 6.8-7.2 pH range.

More recently many pits are blamed on poor quality copper metal supplied from all over the world.

Best bet is to maintain clean pipes and neutralized water.

Galvanic corrosion protection is talked about in old farm houses where wiring may be questionable.

Q. I have a newly constructed home that is just over a year old and has excessive blue-green staining of sinks, tubs, tile etc. I had the water tested and it is municipal water that tests OK. I have been told by the chemist as well as a water treatment specialist that my water is corrosive and the problem has to be electrolysis. My electrical system has been tested and has been found to lose amperage to grounds (e.g.copper pipes, etc.) instead of the neutral ground. However thus far the source has not been isolated. I'm trying to find out the places or areas within the house that people have had experience with this occurring. Can it only be in the electrical system? Can it be in the plumbing system? Can it have to with the electrical utility company or the water company outside my house? Can it have anything to do with the audio-visual wiring or phone or computer network wiring somehow creating a ground loop within the house? I am desperate to hear from anybody who has encountered a similar problem and what the possible causes and solutions are.

Thank you.

Gentle Readers:

This meeting place welcomes Q&As, photos, history, & interesting tidbits -- but it's not a consultancy.

Please engage with others

• When people show interest in each other's situations, the forum is informative, and fun too !

• If people post their own question but show no interest in others', it can quickly become a long string of unanswered questions

Q. We have a new construction home that is 2 years old. We are on a private well and the water is extremely hard. The first year we dealt with hard water deposits and staining, and then we installed a water softening system. That helped reduce that problem, and now a year later we have blue water stains indicating copper corrosion.

We have not done any testing to discover the underlying reason for this problem (we are still gathering info). My question is: Assuming the reason is discovered and addressed; is there a way to stop the corrosion or are we destined to have leaky pipes with the likelihood of having to replace them?

Q. I have an artesian well and the pH was low a while back so it tinted my bath tub and my hair a greenish color. Not so fun. The pH has been normal for a while now but the water is still turning my hair a funny greenish tinted color. If anyone knows how to make it so the corroded copper stops turning things green it would be so awesome. please help!

Q. I have .3 to .9 volts a/c on my external water faucets, what could cause this? I am experiencing pin holes in copper water pipes in a nine year old home. From the looks of the pipe, it appears to be electrolysis. The first leak appeared 2 years ago and the latest one week ago. I have a water well with excellent water and live in rural central Texas. The electric company came out and removed the meter and we disconnected the breaker at the well. With no electricity possible to the house, I still measured the .3 to .9 volts at the faucet.
Any ideas? Help.

Q. In my 45 year old house we noticed blue water in our bathtub recently when filled to 8-10 in. The city and province ( state) have all tested and declare the water OK to drink. Then ran a hose from the fire hydrant into my white bathtub, by passing my system, and the water was still blue. tests for copper all indicate level OK for drinking water. my neighbor has the same problem. Extensive testing for organic and non organic and metals all show normal levels for drinking water.
Any thoughts?
Any help would be welcome!

"Practical Grounding, Bonding, Shielding and Surge Protection"


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Q. I am facing a similar problem. There is a tingling sensation when we try to open the taps in the house - kitchen, bathroom … but it lasts only a few seconds - 10-20 sec. Then it's gone for a few hours. The electrician checked the electrical wiring but seems fine. still struggling with the problem.
If anyone can suggest I would be happy . If I find a solution, I will post it to you.

Gentle Readers:

This meeting place welcomes Q&As, photos, history, & interesting tidbits -- but it's not a consultancy.

Please engage with others

• When people show interest in each other's situations, the forum is informative, and fun too !

• If people post their own question but show no interest in others', it can quickly become a long string of unanswered questions

Q. I am curious about the forming up of the 'Blue/green' water in copper pipelines, just wondering if these pipes are soak in water before a huge tank to allow these pipe to be oxidised will it help?
Basing on my understanding, these phenomena is only subjected to NEW copper pipelines.
My prime concern is to get an answer not by purging the pipelines or flushing the pipes with chemicals.

Q. My problem is also with copper pipe failing, my Question is will a strong radio signal promote electrolysis in copper pipes? If it can does anyone have any suggestions?

Q. I'm not seeing many answers here, but I will post what I'm seeing and see if it helps anyone.

My house is 6 months old and it gets used only every few weeks. Every time we have returned the water will flow bluish and you can find blue crystals in the aerators and showerheads after running the water. The crystals look much like copper sulphate.

The water supply comes through black Polyethylene piping and connects to the copper system in the house. The electrical system is not connected to the copper pipe at all, but is grounded via grounding rod outside. There is a DC potential of ~0.5 volts between the metal spikes embedded in my foundation and the copper piping in the house. When the main circuit breaker is turned off, the potential remains.

Add to all this that my foundation is insulated on the outside using pink styrofoam insulation, but is attached using special nails with 2" diameter heads. I measured the potential between the nails and the electrical ground rod to be about 0.3 volts (the measured points were only 12" apart). This may be the multiple grounds that Eric referred to above.

My big problem is that my shower heads are clogging and it appears that I will have failing pipes in the near future if this is not resolved.

Local water quality is excellent with a PH around 7.0. Neighbors and local plumbers do not have/have not seen this problem.

So if I have a distant earth problem, will providing a better ground than the foundation be the solution? or will I just create new problems by grounding the pipes to a new ground rod.

I'm going to get to the bottom of this so any leads from here are greatly appreciated. A solution is even better.

Ed. note: Hi William. Sorry, but this is a free public forum not a paid consultancy, so human nature dictates that there will be more Questions than Answers, more people concerned about their own problem than soving someone else's. Still, there are many generous & helpful answers above and there will surely be more below

Q. Following Steven Wann's answer, I have another question.
We have a new vacation home in NH, and are experiencing the blue water problem. I called the town water person (we town water not a well), and he said they keep their pH at about 8, so that should not cause the copper corrosion.
Our electrical system is properly grounded, as far as I am told.

Is there another answer to this blue water thing? We are going to have the state lab test our water for potability.

The toilet tanks show blue tinted water, and the toilet bowls of the lesser used bathrooms have a blue stain that is difficult to remove. This does not occur in the bathrooms that have been used more regularly, say once or twice a month.

Any suggestions?

Thank you.

Q. I have been living in the same house for 26 years using the same artesian well and copper water pipe system without any significant problem. Over the past three years we have been getting a bluish-green stain on our white bathroom fixtures. It has gotten worse and worse to the point of frequent cleanings and I'm worrying about the safety of the water.

I recently had the water tested and it was normal except for the pH level which was 5.8; however, 26 years ago it was 5.6 and I had no staining problems then. The only thing I done to the system recently was about four years ago the submersible pump was professionally replaced.

Any ideas?

"National Electric Code"


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Q. My copper pipes are underneath my house, Katrina flooded my house with 4 feet of water, should I change them.

A. No, I don't think so. If they are exposed, you might rinse them with fresh water though. It is very common to use copper water pipes even for direct burial in the ground.

Q. YES I AM A DO IT MY SELF PERSON AND I NEED TO INSTALL A NEW HOT WATER HEATER MY PIPES ARE COPPER AND I WAS WONDERING SO THAT IT WILL BE EASIER THAN USING A TORCH CAN I CHANGE THE ENDS OVER TO PVC

A. PVC is a nice material in many ways but has a very low temperature limit making it unacceptable for hot water piping in general, let alone connections right at the water heater. Get a handyman book on the subject of soldering copper pipes, Barbara; it's relatively easy. These days you can buy copper fittings with the solder already applied, and it makes it even easier. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

Ed. update: A technology we hadn't heard of in 2007 is very popular now, and should at least be considered: SharkBite copper fittings.

Q. My husband and I recently bought what we thought was our dream home until we found blue granules in our toilet tank and toilets and then started noticing a blue spot in one of our sinks. Our community is about 1 year old and several homes are having the same issue. The water has been tested at the hydrant and tests normally(so our H20 supplier says)and the homes have been tested and are properly grounded. What else could be the problem? Also, how hard would it be to reinstall plumbing for an entire home, if it is even possible? I have children and a newborn and have read that it is toxic to ingest a certain amount. Does anybody have any other solutions for me to try?

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