EPIDEMIC OF LEAKS and CORROSION CELLS

Pinhole leak caused by a Bimetallic Corrosion Cell

When two different metals such as copper and steel are connected together, especially in the presence of moisture, the voltage difference, resulting from their differing physical properties, will cause an electric current to flow from the metal with the higher voltage potential to the metal with a lower voltage potential.
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At the same time electrons flow on the metal from the one metal to the other. This is called a "bimetallic or dissimilar metal corrosion cell."
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Recall that corrosion results from an electrical release of energy in the form of electrons and DC current from a metal surface, especially when moisture is present. If an insulating barrier has not been applied to block the flow of electrons along the metal surfaces, then, corrosion is assured.
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The currents are small and corrosion sufficient to cause pinhole leaks takes time; but our CV infrastructure is reaching a point in its life cycle where such leaks are undoubtedly possible.
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Proper and careful plumbing and construction techniques requires the application of high dielectric strength barriers (insulation) to every such union of pipes made of dissimilar metals (Steel and Copper). Modern installation of under sink traps usually employ PVC to avoid any such corrosion issues.
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When our buildings were built was this problem carefully considered in plumbing all of our structures? Do we have any cases of copper pipes within walls or slabs coming in contact with REBAR or metallic studs? Look at your under sink traps; do you see copper pipe emerging from the wall joined with an old style steel trap?
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Is this technical issue the cause of our epidemic of water damage and mold; I do not know for sure, but it is certainly worth looking into.

Dave Israel