Green Sand in Water Line

It sure sounds like copper corrosion! (That icky, flakey, green residue that copper rusts into.)

If the building is only 10 months old, copper corrosion already seems odd... it might be coming from the water heater (?) or perhaps a particular section of copper joints/fitting/pipes.

I don't think it's external. Should be something inside the building - or at least on the building side. It could be the connection to the city source pre-entry to the building (but the city water shouldn't have that much copper rust).

You don't by chance have a dolomite (Mg & CaCO3) water supply over there? What is the pH?

The green stuff seems to be the same as a mixture of CuCO3 (green) and precipitated calcium i have witnessed in my swimming pool.

I was using super saturated dolomite water from a bore hole (cavity 400m below the surface) to fill the pool. the pH was above 12.

It was a nightmare to keep clean. At some stage somebody suggested adding CuSO4 to solve the problem. It actually work well until the first thunder storm. The clear water actually turned green before your eyes.

Another thing about the precipitated calcium is that it will gather in lower or side sections of pipelines and will be washed out when first used.

Are you sure the water is coming from the lake rather than well water? (One taste should tell you because well water up in the Chicago area is some of the foulest tasting stuff I have come across. The limestone aquifers there make some extremely hard water and I have seen precipitates form in the stuff when simply boiling it.

If its the well water, then its very likely that you are getting copper carbonates percipitating out due to the extremely high hardness that you have there. Lake water is much less hard.

From the City of Chicago web site

From this I presume lake water, since the building is in city limits and close to the lake. I appreciate your comment on the dolomite, there is a fairly thick formation of limestone and shale 50-75 feet below ground level in this area.

Water main into the building is suppose to have a double di-electric isolation, per owner requirement.

Second floor locker room (with lav) is next to second floor boiler room and dom HW heater, so if the issue is with the water heater, this is the closest point.

next to second floor boiler room???

Are you sure you don't have some kind of cross connection or contamination from here that the Inspector "missed"?

After all, you are in Chicago, the land of corrupt Politicians and bureaucrats.

I refuse to answer the political insinuations on the grounds that I might incriminate myself! However some people do feel we have the best politicians money can buy!

The heating HW system and the domestic HW system are independent of each other. Even though the heating boiler feed had a RPZ backflow preventor on the water feed, the city inspector had the contractor add a break tank on the cold water supply for positive system isolation.

Unfortunately I am being kept at arms length from this issue, so I have not physically seen what is going on. Alledgedly this is only happening in the second toilet room from the boiler room. The closest toilet room is not affected.

The owner is very particular about system grounding, and each electric room and comm room has a ground bus tied to the building ground system, but that doesn't mean one of the subcontractors might have taken a shortcut some how.

Isolation between separately earthed pipes would mean that there is no shorting metal between so-called Grounds. That would mean any current passes through the water itself - ideal for encouraging electrolysis, I would think.

If the problem is only occurring in the 2nd floor lavatory and not the other areas, it is fairly likely that the problem is associated with the travel of the water through the piping to the second floor. I would suggest that tests be conducted to determine the difference in water chemistry for 1st floor water and 2nd floor water locations. It should be possible to isolate the contaminating ion(s) via ICP analysis. Then you would have a more accurate idea of the source.

You must have a current loop on the second floor or between the first and second floor.

Qqberci, you and Mr. McGill may have a point. I will keep this in mind as a possible issue. Thanks.

Hello Ried,

As was said by cjMgill (not sure of the spelling sorry) you are working in a giant battery! I never thought of it before but you have copper and other metals and an electrolyte (water). That,s what it sounds like to me.

I am trying to find the thread it was posted in but I have rather a lot on the go. I will keep looking and post it for you.

Take care and have a great new year!

Is this Connecting Ground wire to Copper water pie the post? not much about corrosion I'm afraid, but good info on why it is no longer acceptable to mix sparks and water with grounding systems.

Some pictures of the sand and faucet.

Could electrolysis cause the sandy material in addition to Cu corrosion?

Thanks!

The sandy material is calcium granules. Quite normal in hard water areas.

Color is from the copper. This much color is unusual in a fairly new system. If the system sits for long periods between usage and there is something acidic in the water, you may see color.

Most copper water supply systems will not have enough copper oxide develop over the life of the system to color the water noticeably.

3 questions:

1- Do the granules happen throughout the building, just not green?

2- Is the green coloration isolated to one section of the system, hot (you mentioned, but is it distinct) but not cold, etc?

3- is the water heat electrical, stored, on-demand, shared?

Drain a little water from the water heater and see what you find.

To solve this may require a water softening system. If that is the case, you can't be the only building in the neighborhood with this symptom. Have you checked around?

A simple pH test might be helpful.

I can't help wondering if you have had any conversation with the water supplier?

You know we are all waiting to see how this one turns out! A true mystery, but like all mysteries, there is an answer.

I certainly appreciate all the help, and would be glad to post a "final" answer if and when I find out.

To answer question three, water is heated by gas and stored in a separate storage tank. A circulating pump runs the water between the storage tank and heater. There is a separate recirculating pump and system for each floor (3 floors).

I will pass on the other questions, and post answers when I get them.

I had the same problem a few years ago and can only advise you as to what I found out after investigating and what I did to rewsolve the problem.

The green crud would clog the aerator screens on the faucets and the clothes and dish washer solenoid screens. Next noticed an increasing accumulation in the bottom of the water heater (residential not circulated loop). When I did some piping changes I noticed some of it inside the copper piping but not a whole lot. Water was city water with the majority of it coming from wells. During the winter months sometimes the water was treated with so much Chlorine that you smelled like it after taking a shower.

Found out via some investigation that: Water company treats with more chlorine durring the winter due to their mix of well, surface canal and river water; water company had motto that "their is never too much chlorine so go heavy on it"; I tested some of the green chrud for chloride and it was positive; the green crud was exactly the same as the green solid that you get when you flux a copper pipe with soldering paste (Zinc Chloride based) and you don't wipe the joint clean after soldering it; a water filter placed near the entrance of the water service entering the house had very little, if none, green crud in it and one placed in the hot water outlet of the water heater accumulated the green crud.

The problem is Copper Chloride. It is more soluble in cold water than hot. The chlorine treatment of the water, and it is probably in excess of what it needs to be, provides the free chlorine. Your street distribution lines are probably cast iron or plastic so the chlorine doesn't react with them. When it gets to your building it begins to react with the Cu piping to form a precipitate. It doesn't show up as much in the cold water since it is more soluble in cold water. When the water is heated in the tank heater the precipitate begins to really form due to the lower solubility also it collects in a greater rate since the velocity of the water is nil in the water heater compared to the velocity in the piping. Once you get an accumulation of the crud in the tank the precipitation rate increases because the material already in the tank tends to "Seed" the soluble materials into the precipitate (remember seeding crystals from grammar school science class).

Practical solutions include:

Persuade the water company to cut down on the excess chlorine treatment, possible but not likely.

Add a chemical treatment system to react with the chlorine before it gets to the heater, possible but expensive.

Add Chlorine removal cartridge filters (really just activated charcoal) before the water heater, possible but high filter replacement costs.

Put a particulate cartridge filter, either the string or pleated paper type, in your hot water circulating piping as it leaves the water heater tank. Also drain off a few gallons of water from the bottom of the water heater tank each month to remove any particulate CuCl, silt and dirt from the bottom of the water heater tank. The filter doesn't have to be big, just large enough to handle the gpm that is circulating through the piping. Also best to use a metal housing equipted with a bottom drain for the filter housing and make sure the filter media can withstand the temp of the hot water. Least expensive and least combursome to maintain.

My situation was in a 3 bedroom house so we weren't putting a lot of water through but after I had to replace the water heater because of the "bumping" caused by all the percipitate in the bottom of the heater I made sure the filter was in place and that I drained 5 gals out of the bottom each month. Never had to replace a faucet aerator or wahing machine solenoid after that!

Good Luck

Disclaimer- The aforementioned posting is based on facts as they happened and how they solved a problem. If you don't agree with the chemistry involved, investigative methods utilized or conclusions derived from them, don't bother to disagree- just use your -del- key! It will help you calm your agressions and it won't bother me at all.

I hope this solution for the green crud works for you, it did for me.

City of Chicago has 2 water purification plants, Jardine and South plants. Since building is on north side of town I assume Jadine is supply point. Chicago website did have reports on 3 water samples for 2008. Water temp at inllet ranged fro 1°C to 20°C. Inlet TDS 145 to 170 mg/L, oulet TDS 157 to 176 mg/L. Hardness inlet 130 to 146 CaCO3 mg/L outlet 134 to 144 mg/L. Inlet pH 8.09 to 8.36, Outlet pH 7.69.

My impression is this is fairly good water quality.

The chemistry you are describing sounds like it might be system wide, what is strange in this case it appears to be one faucet. However you are on a parallel track with other responders, so I will keep it in mind.

I have forwarded the following questions to the contractor:

From the photos, it appears that either Cu corrosion is discoloring sand
or copper cloride is being formed.

How often are faucets in 212 and 211 used? Is 212 used more than 211?

Has Water Heater or Storage Tank in boiler room been flushed? Any sign of
sand or copper corrosion at this point?

Can the plumber do pH testing on the water? Is pH higher than 8.0 or
lower than 7.0?

Could this be an isolated case of electrolytic corrosion from a ground
loop in the hot water system? Is a Comm Room 210 ground somehow "leaking"
current into the hot water pipes?

When I hear answers I will pass them on.

There was a project meeting today at the job site. The story I hear from our project manager is the contractor thinks there is a bad solder joint that is causing the Cu corrosion and causing a salt to precipitate out looking like green sand.

Since this problem is only occuring at one location, the explanation sounds plausible and unless you hear otherwise, I consider this problem solved.

Many thanks to all who responded, and give each other GA's for the helpful replies given.

For me, this explanation does not make any sense, however I will find it quite interesting if the problem gets solved.

Please keep us posted, thanks.

In my limited checking, I did find a reference "someplace" on the web that over-fluxing a joint with Zinc Chloride cold cause corrosion problems. Wish I could remember the reference. If the problem is solved, I doubt if I will find out too many details. But I will post what I do find out.

I just love learning the rarely mentioned fine points that might in other contexts go unnoticed.

This raised my curiosity and I went looking, found this video, and the afterthought detail at the very end may be of great interest.

It could be that someone has used the copper piping as a 'ground' instead of a proper ground. This use to be a common practice. Copper water lines also use to deteriorate in about 10 - 15 years. Now with proper grounding typical, typical copper water lines last many decades.

Were you ever able to find out what the green sand actually was and were you able to fix it?

I have heard nothing from the client or the contractor since Post #22.

Yes I have been away from CR$ for a while!