I am having a problem with my upstairs water. My two bathrooms on the top floor of my house seem to get a black coating on the showerheads and faucet taps. It ONLY happens to the water on that floor. All of the other faucets and showerheads seem fine. I have owned the house for four years and suspect that there was a leak between that floor and the one below it sometime before I bought the house. Someone told me that there may have been a piece of cast iron pipe welded in between the copper system. Is this a possibility or is there something else I should be looking for? And if there is truth to this, how urgent is it for me to find and fix the problem?

It would NOT be a cast iron pipe, nor could it be soldered in, so whoever told you that is definitely mistaken. A steel pipe would give "reddish brown" water but no black residue. In fact, I cannot think of anything in the water that would leave a residue like that.

Something like that is unusual I have seen it before though
It is not however from cast iron piping or even galvanize.
It can be from a piece of black iron pipe attached to the water line
If that is the case you will want to have someone check it fast.
Black iron will rot and cause a leak on the water line

I'd try to determine if is it growing bacteria or debris in the water.
Best Wishes

Thank you all for the information. I am going to have to do some detective work then.



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BLack pipe "Rusts" which creates a reddish brown color to the water NOT black.

a decaying rubber washer somewhere in the system could create black specs giving the impression of soot.

Now you are "grasping at straws". A failing rubber washer in the valve would NOT contaminate the entire system. In fact it would only affect the item connected to it.

This issue only happens above where i suspect there was a previous leak. I am going to open a window in the wall and take a look. Is it possible to weld another pipe to copper or must copper only be welded to copper? If this was a mold or bacteria issue how do resolve it?

using the proper transition fitting/s, any pipe can be attached to any pipe.
as for mold... a small amount can be treated with a bleach solution. a much larger amount must be treated by a company specializing in mold removal.

After some inspection inside the walls, I found nothing but copper pipe. But, when I looked at the pipe coming out next to my shower that feeds my washer/dryer, it is definitely not copper. I Am going to open that wall tomorrow and inspect some more on the top floor. Is it possible that could be the cause of this?

if the pipe you discovered feeds the laundry but you are getting black residue in the showers then it is highly unlikely that it is the culprit..

I suspect that the problem isn't the water, it is probably mold spores from the moisture and inadequate venting.