Copper corrosion and blue water in residential water system
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?Tony Warrick
civil engineer - Bethlehem, Pennsylvania
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. RET
Brick, 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.
Ballarat, Victoria, Australia
It is this website's profoundly sad
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
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?Shirley Canfield
homeowner - Alpine, Texas
A. Hi Shirley Canfield..
I had the same problem. The earth on your house should read less than 1,ohm from any power socket to ground. The earth connection should be made via a dedicated earth cable from your consumer unit to ground via a buried metal spike. If you can feel a tingle ( it's safer to use a multimeter tester) when you touch your water pipes, this is due to the voltage leak going to earth via your pipes rather than the correct route through the earth wire. Try switching off each mains fuse trip one at a time until you locate the circuit that is responsible for the voltage leak (tingle should disappear).Once you have located the offending circuit,unplug each appliance on that circuit until the leaky appliance is identified and have it repaired on bin it. You should then have your earth connection checked out.
Note this sort of earth leak will pepper your copper pipe with pinholes wherever in comes into contact with moist earth, (the higher the voltage, the quicker the holes).Keith Cooper
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 ?
- Dallas, Texas
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,ART CICCARELLO
contractor/designer/builder - NEW HARTFORD, Connecticut
A. What is occurring in your plumbing system is refer to as "Blue Water Syndrome". It is not an electrolysis problem but a water chemistry issue. All new copper piping dissolves at a rate of .001-.003 per inch, per year during the first few years of installation. Blue water occurs many times in homes which are larger and only a few occupants or if a soft water conditioner was installed before the piping was ever used and is over softening the water. There are a few other reasons why you can have an accelerated rate of copper dissolving as well. Some of which is if the pH is below 6.5 copper solvency occurs. In addition the changes made as part of the EPA Safe Water Act of 1991 removing of NOM's from the water has caused a lack of the protective patina which occurs as the copper is dissolving.Steven Wann
- Santa Ana, California
The Blue Death
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.Stephen Gal
homeowner - Wyckoff, New Jersey
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?
- Rochester, Washington
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!Christine C
student - Concord, New Hampshire
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 help help......
rancher - Mullin, Texas
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 help would be welcome!
- Toronto, Ontario, Canada
A. Too many earths could explain most of these problems. I am an electrician turned science technician. Electrolysis is caused by DC current only. I found pin hole leaks under an earth clamp. My explanation is that a DC current is flowing from one earth on the water system to a second earth also connected to the water system. A DC voltage often exists between distant earths. Examples of separate earths are:
- St. Briavels, Gloucestershire, UK
Practical Grounding, Bonding,
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.
- Delhi, India
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?Miles Berry
- Meridian, Idaho
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 sulfate.
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.
- Limerick, Maine
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.
- Lexington, Massachusetts
A. I do have a solution although it is costly. Replace the copper pipe system with a PEX system. If you are on a slab, run the pipes down from the ceiling. PEX has been used in Scotland for 30 years very successfully. It is being used in new developments in the local area. I am a homeowner and live in a 100 unit duplex/triplex set of condominiums. Built mainly in the 1976 to 1985 era. We have had 5 major pinhole leaks in copper pipes in last two years. Three of the leaks were under cement slabs. I have been trying to find the cause with no success. I have talked with water analysis engineers, had lab work done on the water and the pipes and I still have no answers about cause and repair. I have discussed the problem with people from Alaska to Florida. No solutions After two years of research I have come to the conclusion that copper pipes and water don't work together and nobody knows why.Donald H Leo
- Lacey, Washington
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.
- Westford, Massachusetts
A. I'm an electrician, I can only say what a properly grounded system should consist of, according to the NEC. The neutral (in the main panel or first main disconnect) should be grounded to the Copper water main before the water meter(the water meter should also have a jumper around it,to provide continuity if the meter is replaced).This is one method other methods are a copper wire embedded in the footing and bonded to the rebar(UFER GROUND), or if a steel building, using a steel beam as the main ground. The code then requires an additional(supplementary) grounding rod(actually two unless the electrician can prove that the one rod is 25 ohms or less to ground). So usually two 8' ground rods are driven and connected to the water pipe as well.
- Denville, New Jersey
National Electric Code
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?Sarah Bowerman
new home owner - Hutto, Texas
A. While proper grounding is important one thing that I have noticed in my area involves the water chemistry. I have a handful of customers in a new housing development that are seeing this staining. Some have water softeners and some don't. The problem comes from the incoming water. People hear that the pH is around 7.2 (pretty neutral) and assume it has to be the electrical system. I disagree. You need to have a water analysis done and look for a few important things. What is the copper level at? What is the Dissolved Oxygen level? The oxygen will start the corrosion process of the copper that is in solution and in some cases from the plumbing itself. You are left with a Blue-Green stain or build up and in some cases pin holes in your plumbing.Chris Ray
- Omaha, Nebraska
! I investigated a blue water issue in a town home community my company built several years ago. Several homes in the community (but not all) had the blue granules and staining. We also found evidence of the same phenomenon in a neighboring single family community. We used the same materials and contractors in several Villages, but only had the issue in one. We tested the water, and while the copper content was higher than normal it tested well within the EPA's standards. We had State plumbing and electrical inspectors check the community and all was found to be done correctly (no grounding issues and proper materials and installation). Nothing we did alleviated the problem. I called a chemist at a neighboring Village's water department and was told that some Villages use a chemical to seal their pipes periodically if high levels of lead are found. This chemist said that her Village did not use this chemical because it causes copper to corrode. When I mentioned this to the water department of the Village we had the issue in, they ceased to request any more exploration into the issue by my company. I believe it is still an issue in that community to this day (7 years later), but we have not been involved in it for the last five years.John Yanez
warranty manager - South Elgin, Illinois
A. I came across the following information from the Washington Suburban Sanitary Commission. It may help explain some of the copper pipe problems in new housing:
Formation of a uniform, protective film on copper also depends upon proper flushing of the system to remove construction debris from the inside of the tubing. Clean inside surfaces are essential to the development of protective films. If debris is allowed to remain in place on the inside surface for an extended period of time early in the life of the system, two to three months for example, corrosion can develop beneath the deposits [6,14]. Once started, this type of under deposit corrosion@ will likely continue resulting eventually in a leak failure.
A related cause of copper corrosion can occur when a completed plumbing system is allowed to remain stagnant with residual water for an extended period of time following flushing and testing. This problem has been discovered and identified most often in tract homes and apartment complexes that are often constructed, but not occupied, for a period of time . The initial stages of protective film formation on a clean copper tube surface depend upon a frequent flow of water through the system to promote uniform film growth. Stagnant conditions for extended periods of time, especially when the system is partially filled, can cause non-uniform film development and corrosion depending upon the source of water.
An example of stagnant water induced corrosion is shown in Figure 6. The copper tube sample shown is from a horizontal section of 3/4 inch Type M cold water tube removed from an apartment complex that had been tested for leaks, but remained unused for several months. After two years, leaks began to develop in the plumbing. The upper half of the tube is positioned at the top in the photograph. A residual amount of water remained in the tube following testing, resulting in the growth of a non-uniform corrosion film in the bottom half of the tube. The yellow arrow indicates pitting corrosion that occurred at the water line under the stagnant conditions. This is another example of under deposit corrosion."
- Tupper Lake, New York
Q. Our house in Edinburg, Texas was built in 1996 and we bought it in 2000. I never dreamed a less than 5 year old house would have problems with the water pipes. We put in a water softener at that time, too, but it does not to appear to have helped. We recently went away for the Thanksgiving holiday and returned to a flooded kitchen, DR & LR.
The insurance company will help with the damaged drywall, cabinets, etc, and I paid for the water line repair. However, I am now trying to decide whether to change out all of the water lines.
What are your recommendations?
student - Edinburg, Texas
A. I have seen on the internet Oscillating Rings that take care of rust, lime scale, bio film and various other problems in the water system. I am sure these are an answer to your problems. I have one in my house and it has cleaned all the pipes of calcium build up, including the recurring problems in my showers holes that got clogged regularly.Rishi Dwivedi
- Flushing/NY/Queens, New York
August 6, 2008
Please note that it was a reader not the site's editor who recommended these "Oscillating Rings". I'm not familiar with them but the explanation on their web page struck me as awfully silly. Just my opinion.
August 27, 2008
A. After finding some copper flakes (!) coming out of our bathtub faucet, my wife (with knowledge in metallurgy) suggested we needed to do something, so I read up on corrosion enough to understand there were many possibilities. Also, reading this thread it's striking how very complex the combination of possible factors is for each house. I count 6 possible factors to consider in deciding what to do: ordinary galvanic corrosion (this is common), electrically driven corrosion, pH driven corrosion, oxygen driven corrosion, considerations of grounding pipes (advantages vs disadvantages), and of course the effects of changes in standards of water supply by cities and in grounding, all contributing to possible complex situations.
Consider for instance that even copper tubes are thought to have some impurities that could lead to local galvanic corrosion....
I wonder if using a "sacrificial anode" (a standard part of every water heater) might help in many instances....
For example, your hot water heater anode may be worn out, contributing to increased corrosion not only in the water heater itself, but elsewhere also. One possibility.
Many water heater anodes can be easily replaced, and it's worth a look for a do-it-yourselver that takes simple precautions such as turning off the water at the outside meter after having turned off the water heater and run the hot water out of it, etc. etc.
- Austin, Texas
September 26, 2008
A. I have found many of the comments of great value and there are many good insights. I have done some recent research on this subject and would like to share my 2 cents worth. My initial question of anyone calling with blue/green staining is, "are they noticing staining connected with both the hot and cold water". If the problem seems more prevalent on the hot side, I have suggested checking the temperature on the hot water heater. If it is above 120 deg. Fahrenheit, I suggest that the temperature be reduced to that level. Also with the square footage of homes increasing many homes are equipped with a recirculation loop to provide instant hot water at every hot water location. These systems can contribute to erosion corrosion is some situations and reducing the pumps velocity or turning them off altogether has eliminated the problem.
High levels of Dissolved Oxygen and Carbon Dioxide are other issues that can cause copper corrosion and should be checked. I will not go into electrical cells that are set up in the plumbing because that has been covered in this thread by folks more knowledgeable than myself.
I would just like to mention that in some cases, we have used poly phosphate feed to form a coating on pipes to protect them from corrosion. This naturally occurs when the copper is exposed to hard water but where water softeners are installed on new plumbing or the water is naturally low in total dissolved solids and hardness using poly phosphate can be an option.
Lastly, it is important to realize that once corrosion begins it can be very difficult to stop. With in the corrosion pocket a mini environment is established which can be much more corrosive than the surrounding water. In these situations encouraging the copper piping to establish a protective coating may be the only solution.
engineer - Manitowoc, Wisconsin
March 26, 2009
A. The problem of corrosion and pin hole on the water pipe caused by the water pipe being used as the neutral-to-ground bonding jumper in the electrical panel in your house. You have not electrical ground in your main service per NEC250.Benjamin Du
- Torrance, California
June 22, 2009
A. An entire housing tract in Danville, California had or has this same problem. Bill Watenburg, electrical/mechanical engineering professor at UC Berkeley and radio host, suggested a fix by providing a constant source DC voltage power supply, presumably low voltage, applied between the copper pipes and earth ground. Power supply voltage and connection points were a variable depending on measured results. I don't recall all the particulars. However, the "blue water" situation seems to have stopped shortly thereafter.Jerry Ringtadt
- San Diego, California
September 29, 2009
Q. My wife highlighted her hair and her hair is changing to green,what causes this. my cold water heater is grounded to the electrical system at the hot water heater, I also extended the grounding to the incoming water piping at the water softer, also there is a ground rod with # 6 ground wire.
And my wife is mad about her hair turning green.
- Indianapolis, Indiana
A. I recommend that for a complete explanation of all of the above problems you search on: "stop-pinhole-leaks" and read the information. This is NOT a recommendation of the company but the theory is good and has been used for lots of years in the petroleum industry protecting tanks and lines. That information should end your speculation.Lee Griffith
retired engineer - San Diego, California
December 12, 2009
Q. My home is about 16 years old and I have just had to correct my third pin hole leak in one year. The third since the house was built. It has copper water lines.
I have been told that; 1) bad pipe was used, 2) the lines were not shield correctly and they are touching metal some where, 3) extra hard water causing corrosion, 4) electrolysis due to improperly grounded electrical.
I have not had "blue water". I have a water softener.
So far my possible suggestions for correcting the problem have been: 1) repiping the house -very costly, 2) Having my water pipes coated with epoxy from the inside - maybe not as costly as repiping, but expensive, 3) grounding the water system with a ground wire from the cold input pipe to the hot water heater, 4) Re-grounding the electrical.
Needless to say, I am confused, but I need to correct the problem. It is costly to repair the leaks and damage.
The previous answers don't directly address my issues. Any help will be greatly appreciated.
Home owner - San Antonio, Texas
A. I stumbled on to your site looking for something else but I'll throw in my two cents. I'm an electrician. I was working for a Country Club and members complained of "tingling" sensation while showering. Sure enough there was about 5 volts AC on the plumbing lines to Earth. I checked all grounding and found nothing wrong. We tried turning off different circuits with no luck and finally shut down the entire building. The voltage was still there. We thought it might be coming from the phone lines or cable and eliminated those sources and the voltage was still there. I called the power company and they sent out a tech. I duplicated what I did with him and he was as baffled as I was. A few days later the power company sent out an engineer and he told me he had seen this before. He called out some linemen to check the connections on several transformers in the area (mounted on the ground with underground services - not on poles). He found one about 250 yards from the building with a bad neutral connection. They corrected it and problem solved. No more stray voltage and no more tingling. Who would have thought a transformer a couple hundred yards away could induce stray voltage into the copper plumbing lines because of a bad neutral connection?Wesley Burchardt
- Lutz, Florida
February 18, 2010
Q. I too stumbled in here looking for an answer. I am renting a business location which was built about 18 months ago. We have been doing some work and had not moved in yet. The water meter on the ground floor (interior wall, room heated to 60)had the bottom cracked open and sprayed the room with water 3 inches deep. The water was full of teal green precipitate. The copper pipes did not freeze as it was not that cold outdoors, and other people in the adjoining spaces were using water without a problem.
The DEP said the meter had to have frozen, but I know that did not happen on a heated interior wall. I am concerned because of the damage and do not want this to ever happen again. Could there have been too much pressure in the line or was this a defective meter? or could the copper precipitate in the water every where indicate some major failing?
- Staten Island New York
March 15, 2010
Q. Hi my name is Sheila Winters. My husband and I built our house 8 years ago and we have our own private well. We have a serious problem in our hot water system but only on the bathroom circuit only. The problem started about 7 mths after we moved into the house we noticed that particularly in the winter months when the water is being heated there is a terrible blue staining coming through onto the bathroom appliances i.e., the shower and bath but not the toilet and only occasionally on the sink.We have asked 3 or 4 various people about this and nobody knows. It is also interesting to note that the kitchen hot water is on the same circuit but to date has not caused a problem. My husband and I are baffled as to what this is and why it only happens on the hot water system and particularly in the winter months. The hot water storage tank is clear on the inside. we are worried that there may be a health risk in using the water and are keen to resolve the issue Please help.
home owner - Ireland
A. Plumbers and electricians often confuse or call Galvanic Corrosion "Electrolysis". Any internal corrosion of a pipe will not be caused by stray currents occurring on the exterior of a pipe. Blue water is a water chemistry issue. Remove your water softeners so that your copper piping can oxidize and develop its patina and a nice shield of calcium carbonate. Using pre-oxidized pipes, not a bad idea. External corrosion of your copper pipes may be due to SOIL CORROSIVITY or because a HOT water pipe is in close proximity to a COLD water pipe. Copper is susceptible to thermogalvanic corrosion. Ammonia and nitrates are also bad for copper so if your copper piping is in soil, you should have your soil tested.Eduardo Hernandez
- Temecula, California
July 1, 2010
A. Wow, lots of issues with copper piping, nary one answer for all, and some are close but none more informative than the copperinstitute.org. I've been plumbing for 30 years, and have seen, heard and read a significant amount of information about this subject. I'm a plumbing contractor, IAPMO, ICC plumbing inspector, and a certified Cross connection specialist (water contamination specialist). First things first, any change in the color of your water is considered turbidity, which could be caused from organic and inorganic dissolved solids. To be safe, I would have the piping system professionally cleaned as specified in the Uniform Plumbing Code with a mixture of sodium bicarbonate, this will neutralize any acidic issues, and give you a fresh start. Second, the ph of the water is essential to a healthy copper plumbing system, therefore a municipal water system should be used, not well water. Third some copper piping was found to contain steel coming from mexico, which will cause in holes. Fourth, copper piping will expand and contract with temperature, and if uninsulated will rub on rocks, etc. and cause pin holes. Fifth, Soft underground copper tubing may be deformed or pinched during initial installation which may cause water velocities to wear at the deformed areas of piping causing leaks. Sixth, Non water soluble flux, or acidic flux (now banned) may also cause corrosion, as most fluxes were heat activated, this also may affect hot water lines. Seventh, Dissimilar metals, will also cause corrosion, as will acidic pipe dope compounds. Eight, Soil composition, is also an issue and is referred to as "Hot Soil", and may have a ph issue, or is high in salinity. Nine, any electrical current found in a copper piping system is of great concern, as this is the most under reported cause of death of plumbers who work on water systems, and is NEVER OKAY, the water pipe should have at least 5' of direct burial water main giving the system a proper ground, and should never be dependent upon a grounding rod that may not extend 9' down, or is only tied to the rebar in the foundation. Tenth, there are chemical treatments available for caustic water, and you should contact your county health department for the appropriate approved treatment should you need it. Pex is very durable, and has been around europe for some time. The fittings are not copper or brass, and should provide years of trouble free service for anyone with well water or issues unresolved concerning a dependable and potable water supply.G. Lowry
- Temecula, California, U.S.A.
January 26, 2011
Q. I have home built in 1998 and had many pinhole leaks in copper pipe mostly around water heater in mechanical room. We are on well water which is acidic and has many "particles" along with nitrate in it. Did lots of reading as our lines are grounded as recommended. Have the blueish water, pinhole leaks and sometimes rotten egg smell. So after much reading began to suspect its a water issue. Discovered many water companies sell units designed to take out the particles such as iron, magnesium and sulfur and then the water goes through water softener and by time it hits pipe water is less able to cause an electrical charge in pipe. These units are becoming very popular as people learn about them and I am on the verge of getting one. The are called iron and magnesium reduction tanks for use with well water. My water tests positive for nitrates so it is a way to get our water as healthy as possible. I have a water softener that has reduced the amount of pinhole leaks greatly and feel this may help to further reduce them even more and maybe even stop them. Spoke with well specialist and he agrees the well water is an issue. I have replaced as much copper pipe as I can. I really believe the water is the cause. Copper pipe has been around for a long time and just recently more and more people having problems? Either the copper is made much weaker or our water has changed or both?Karen W
- Twin Falls ,Idaho USA
April 19, 2011
Q. Questions regarding blue water.. Attention please, Steven Wann.
We are a high end residential builder and recently encountered the Blue Water Syndrome for the first time in over 30 years. The home is very large, almost 30,000 sq ft, and occupied by a couple and their two children. Now, a year and a half after occupancy, the homeowner has noticed blue rings at the water line of the master tub, blue staining of the marble floor directly below the shower heads, and a blue ring at the water line in the toilet water reservoirs. All the staining, other then in the toilet reservoirs, is extremely light. The residence has a very sophisticated water purification system with Water Softening equipment, Reverse Osmosis, Charcoal Filter, etc. (Interestingly, two bathrooms, one in the Gate House and an exterior bath, that are located BEFORE the filter system do not have any signs of blue water staining). We have our electrician checking all the copper piping for any electrical charge, to confirm the grounding is sound, and we have our plumber checking all the filters for contamination and visually inspecting to be sure there are no electrical conduit or metal bracing, etc., touching the copper.(Although the mechanical areas had been checked very thoroughly during construction to be sure that this condition did not exist).
These are my questions:
1. Does misc. light contact between different metals really create that much deterioration of the copper?
2. If there is electrolytic dissolution, how quickly does the water clear once it is resolved?
3.Are there agents used to flush the system to accelerate the clearing of the pipes?
4.Why would this blue staining appear a year and a half after occupancy.
5.I was told by someone that they had encountered similar blue staining, only in one bath that HAD NOT had water run through the piping before the Water Softening System was operational. The problem was resolved by shutting off the Water Softening System for approximately a week and running untreated water though the plumbing. Does this make sense?
Please, I'd appreciate any advice anyone might have regarding this situation.. Thank you.
Construction - Los Angeles, California
A. Moved into a house that is 6 years old and water on mains fine. However after switching to tank water (tanks a couple of years old) we have the blue residue. Have been told possibly the pH of the tank water is affecting the copper piping. Don't yet know the solution but will update this if we find one. Meanwhile I am switching back to mains water.Andrea Excell
- Regional Victoria, Australia.
June 19, 2011
A. I run a small water testing laboratory and have been involved in many such cases over the last 15 years.
I see 3 different types of corrosion.
1. The water is aggressive (low pH,iron, nitrate present or calcium and magnesium absent i.e., soft water). Hard water is often not the cause of corrosion as it tends to leave a protective calcium coating on the inside of the pipe. It does leave a deposit in the jug.
2. There is a mixture of metals in the plumbing system. typically iron, zinc (from galvanizing) and copper.Recently I have been involved with a coastal location with under floor aluminium foil which was in contacted with the copper plumbing. In this case the problem was only measurable during an easterly storm when the sea spray aluminium insulation and iron nails were creating a battery cell.
This type of corrosion is galvanic and generates a DC current. This can be measured. Reverse polarity of probes reading should also change polarity. If it doesn't, then there could be and AC component to the current leakage.
3. An electrical device, this includes the power meter, maybe leaking a small amount of AC into the electrical system. Dishwashers, water pumps, waste masters,washing machines etc, can all be responsible. Modern devices often have switch mode power supplies which can leak current. Unplugging items from the electric sockets.
Checking for electrical leakage is not easy and requires methodical recording of MV readings as you go through the plumbing system.
I usually start with a water test. Two sample are collected first thing in the morning (before toilets are flushed and showers are used). Run the tap in the area showing blue or green staining wait till hot water comes through from cylinder and collect 50 ml. Run the cold till for a few seconds and collect a sample. The hot sample represents what has come from the hot water cylinder. The cold sample represents what is in the cold plumbing.
Because chemical reaction occur faster at higher temps (generalisation) The hot sample will be higher in copper than the low sample if it is a chemically aggressive water.
If the cold side has a higher copper content than the hot then there is current leaking into the system. My theory is that the current supplies the energy for the increased corrosion. Cu -2 electrons = Cu2+ This is the conversion from metal pipe to dissolve copper. The process produces current when active.
The copper in the hot and cold can be the same and this can indicate a problem before the water enters the house/dwelling
Shallow bores tend to be soft, have an acidic pH and be low in minerals. Rain water has a naturally acidic pH. If stored in a concrete tank they are often OK (no corrosion due to the concrete hardening the water).
When stored in a plastic or metal tank the corrosion occurs.
If an acid neutralising chemical is added to the storage tank the problem will cease. Re dose when the green/blue reappears.
Points to note: The corrosion is at it worst closest to the problem. (check current leakage around the site of the water leakage)
Solar water heating and gas heated water frequently have problems.
- Whangarei, New Zealand
August 15, 2011
A. What you are describing sounds like a galvanic reaction. Make sure that dielectrics are installed (they look like a gnarled union) and if they are make sure that the rubber gaskets are good not allowing for contact between the copper and galvanized steel.J. Kirk
- Genoa, Illinois, USA
August 15, 2011
Q. Our home was built in 2005 and installed a mega tek geo system. In 2009 we started getting pin hole leaks inside the furnace. By 2010 we had five pinhole leaks inside the furnace. Just recently we got one pinhole outside the furnace just a few feet away. All these pinholes are on the hot water lines. Just this week noticed the first sign of blue staining in one bathroom. Have not had blue water in any other parts of the house. Had electrical system professionally tested and all okay. Well water was tested and ph level was in normal range. We do have a water softener treating for calcium. Any suggestions what is causing these leaks and what else we can investigate.?
Knowing that water does carry current but would plastic insulators between the copper lines prevent any further corrosion?mike veon
- new castle, Pennsylvania
October 27, 2011
i. What has been the copper content of the water in some of these cases in part per million. The EPA acceptable level is 1.3 ppm.John Laurenson
Salter water reef tank hobbyist - St. Augustine
November 7, 2011
Q. I have had blue stain in my sinks for several years now. Have read all responses posted here and don't see any easy solution. I've found one commercial product out there that claims results. Does anyone have any comments on the sacrificial anode made by Copper Knight?James Haberberger
- Leavenworth, Washington
A. I am a registered corrosion engineer in California and have worked on several copper corrosion issues including a very famous blue water problem in Northern CA.
Internal corrosion of copper pipes, which causes blue water, has nothing to do with electrical grounding. If stray currents will be involved in copper corrosion (very rare) it will be external corrosion of the copper pipes not internal.
My experience is that internal corrosion is generally caused by bacterial corrosion (generally stagnant water or water with inadequate residual chlorine), leftover flux during pipe installation, erosion corrosion due to high water velocity such as in recirculating water in hot water systems.
Not knowing all the details, I can suggest the following:
Install dielectric unions between the water heater and the copper pipes.
Turn off the recirculating water pump and see if the problem goes away in the hot water pipes.
Check the residual chlorine at the taps and see if it conforms to the water District standards (greater than 1-2 ppm comes to mind)
If the problem still persists, call a local corrosion engineer. Good Luck
- Danville, California
March 5, 2012
In 4/2006 installed a Paloma tankless water heater for whole house-love it. In 1/2007 installed Kinetico whole house salt exchange water softener.
Within about a year green stains gradually built up in both bathroom tubs/shower areas. City water tested as normal. Copper bypasses were placed outside where the softener was installed with no improvement.
Company finally checked household water which confirmed higher copper levels. More copper wire bypasses were placed around water heater which led to some improvement.
Several (4-6) months ago we noticed cold water input copper pipe abutted the metal tank housing where we then stuffed insulation.
So far it appears we corrected the problem-fingers crossed!
- Metairie, Louisiana
March 11, 2012
Q. I have purchased a home in cape coral Florida. I have gutted the home and am told while it is gutted I should replace the plumbing. It now has copper water lines in the slab. The house was built in in 1972. There have not been any issues but I am told that in time these pipes will beginning springing leaks and I should run new pipes from the attic down to the faucets. Does anyone know if there is truth to this? I do not not have any blue green rings in my sinks as others had reported. Any assistance will be appreciated.
- Cape Coral, Florida
March 26, 2012
Q. I own an old house with copper piping; we also have well water and have been told we have hard water. We have several leaks a year with blue corrosion at the leak site, and the area will be so thin that it just breaks and crumbles. Would a water softener correct this problem?TERESA A HORROX
- RINGTOWN, Pennsylvania
March 30, 2012
A. In 1969 or 70 after Christmas vacation I was getting ready for a morning meeting getting a big drink at a water cooler and then before I filled a soda pop can full of water, I allowed my boss behind me in line to get a drink. 20 minutes later I excused myself from the meeting to go to health service, noting I feel sick from that drink of water. My boss joined me. I declined an offer to pump my stomach; I shouldn't have! My boss left; I later learned he had gone to men's room and vomited. He felt better; I didn't; I felt rotten all day. When I poured the soda pop can contents into a glass, the mush was too opaque to see thru, a mix of green, mint green, and blue-green.
The investigation of the problematic water cooler found:
* In piping the water line to the cooler, the plumber used one plastic fitting in what was otherwise an all copper line
* That to provide a ground connection to d c [direct current] signaling function of a tie trunk circuit of a PBX switcher in the lab at this Bell Telephone Labs location, the design people had run a wire from the PBX to this nearby water cooler. And
* The 4 day weekend was long enough for a lot of nasty electrolysis across that plastic fitting.
I recall in electrolysis experiments I did, using ac didn't do much but using dc much more happened!
One can get DC out of AC by using a rectifier; crystal [radio] sets used a crystal to rectify radio frequency AC into varying [at audio frequencies] DC. Some of these crystal sets used the crystalline structure of steel razor blades. It seems possible to me that nearby radio transmitters [like home electronics or cel phones] or high voltage transmission lines can induce signals into metal water pipes with some flow thru the water at dielectric junctions to copper sulfate/ite crystals in contact with inside surface of metal pipe, thus resulting in rectified [dc] flow.
Another chemical involved in some municipal water is phosphoric acid which is added to the "finished" water to keep lead piping from dissolving into the potable water. Detroit Water & Sewerage Department is one that does this but refuses to say so in their Water Quality Reports. This acid in the water may increase its conductivity, causing increased electrolysis effect.
- detroit Michigan you s of a
August 20, 2012
Q. I have a home built in 1998. In the last 3 months we have had 4 "Pinhole" leaks in our copper pipes in unrelated areas of the house. Investigating online I see this is becoming an increasingly common problem in homes across the nation, and that the latest research leans towards water chemistry as the problem although no one yet has a definitive answer. My question related to the above topic is: What experiences have folks had with PEX piping. I see many folks are going this route, and I read that PEX has been the piping of choice in Scotland for more than 30 years, but I can find no reliable information about the long term history of PEX. I need to repipe my whole house, but I don't want to use copper again if I'm going to have the same problem in another 10 years.
Please help if you can!
Joe in NY
- Pound Ridge, New York, USA
Brass finish sink has a white film on it ... electrolysis?March 28, 2013
Q. I have a Hooker bathroom vanity and sink. The bowl is a baked on brass finish. It was installed during construction and has been in our powder room and used for 8 years. Then two days before New Years Eve this year, we noticed that water that sits in it leaves a white film which we cannot get off. The manufacturer said we can use regular toothpaste or SoftScrub on this bowl. Nothing works. I did fill it partway with vinegar and let it stand and some of it seemed to come off but not a lot. Two things have changed that may/may not be the cause. We installed a hot water recirculating pump in October. Then the first week in December we installed a non-electric Kinetico water softening system with a Chloramine Reduction System which has a large carbon filter. Since installing this we have noticed a green residue accumulate under my electric toothbrush and last week we noticed our bar sink (not used much) had a green residue, like calcium deposits only green, on the outside of the aerator. Kinetico has been out to look over the problem and claims it is not their system but thought maybe we have a electrolysis situation. He feels it is in our plumbing or that maybe the recirculating system is causing it. My thought is, why is it only showing up now? I hope someone has an answer before any damage is done.E A McCoy
^- Privately contact this inquirer -^
March 31, 2013
A. Anything is possible and your sink may be suffering from the chemical or electrical issues discussed here, but I tend to doubt it.
The "baked on" finish on your brass sink is almost surely a lacquer or clearcoat of some sort, and it would not seem strange that after 8 years of use, or an incident of abuse (some sort of chemical like turpentine rags in the sink), for the clearcoat to "whiten". If that were the case, you would not be able to clean it off with anything because it wouldn't be a stain on the surface but discoloration of the clearcoat itself -- and that seems to match your situation as well. It's probably possible, but perhaps impractical, to strip the clearcoating and re-apply it (you obviously couldn't use an oven-bake clearcoat). Maybe if you include a photo people will be better able to advise if it looks like failure of the clearcoat. Good luck.
Ted Mooney, P.E. RET
Brick, New Jersey
April 1, 2013
Q. The powder room gets very little use and certainly has had no chemical in or around it as the countertop is marble. I have filled the sink to different levels 3 times, each one higher than the one before with plain water. It leaves a white coating each time. Is there something in the softened water that would dissolve the clearcoat?EA McCoy
- Nebraska USA
A. That does look like something in your tap water interacting with the clear coat.
Get your tap water tested.
Also get some pH test strips and see if your water is swinging too far towards acid or base (pH of 7 is neutral).
Blacksmith - Boone, North Carolina, USA
October 9, 2013
Q. We had a new solar water heating system and on-demand water heater installed last November. Coincidentally, the town had just repaired water saddles on our street before redoing the road surface. Also, we had just upgraded to FibreOp on our tv/ internet. When we started to experience blue water from our taps, both hot and cold, we contacted the solar installers to see if there would be any system or electrical cause and they told us there shouldn't be. But here we are, almost a year later with the same problem and no idea how to go about fixing it. We don't remember the blue before this but had had a recent discolouration (brownish/greyish) in our water from the hot water tank that we had only had in operation for 8 years.
All the above information is very interesting but we are unclear as to the order of steps we should follow. City? Electrician? Plumber? Etc.
Thank you for any feedback or advice you may have.
- Wolfville, Nova Scotia, Canada