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Copper corrosion deposits in tub?

We recently switched from a galvanized water supply line (that failed) to pex, and added some new copper supply lines. We're getting a blue-green deposit in the tub where the spout drips while we are showering. This never happened in the 20 or so years prior to the changes described above. I'm worried about corrosion inside the copper pipe, possibly from electrolysis or from wrong flux. Anyone know what's up with this?

Re: Copper corrosion deposits in tub?

electrolysis only happens when joining dissimilar metals, not between Copper and plastic. If any of the connections between the Cooper and plastic have other metal parts then yes and only when those material are upsteam from the Copper. Sounds alot like purple primer residue though?

Mark P.
Re: Copper corrosion deposits in tub?

You can not used PVC for water supply only drain lines.
They have couplings to conect galvinized to pex or to Copper.

Mark P.
Re: Copper corrosion deposits in tub?

When you solder to a galvinized pipe the heat will loosen any film around inside the pipe is probably what you are getting it should go away.

Re: Copper corrosion deposits in tub?

Without knowing an seeing what was repiped and what was left unchanged, there is no way to guess why you get the green stains.

Re: Copper corrosion deposits in tub?

I'm not certain about the deposits, but if I find galvanized pipes anywhere in a system and it needs repairs, I replace everything because it's all the same age and if one area failed the rest isn't that far behind. I cannot fathom why the plumber did not just run PEX throughout, but mixed types of piping instead. As easy as PEX is I'd much rather do it that way, but that's just me.


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