Copper and Galvanized lines in contact?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jeffeverde, Sep 6, 2010.

  1. jeffeverde

    jeffeverde Member

    Sep 21, 2009
    Late 40's house - replumbed to copper. Outside the service entrance, I've found a maze of buried new and old lines, with a number of copper and (out of service) galvanized lines laid across each other in direct contact. The galvanized lines show significant corrosion where they're in contact with the copper lines, and of particular concern is a still-in-service galvanized natural gas line in firm contact with a copper line.

    I assume that (a) this is not a good thing, and (b) the copper and galvanized lines should be seperated/insulated from each other?

    On the gas line, there's significant corrosion bloom "bleeding" from the galvanized line to the copper. At what point should I be concerned that the gas line needs replacing?
  2. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA
    zinc ( the coating on galvanized pipe) act as a sacrificial anode when near a more noble metal ( copper ) . Dampness in the ground provides the electrolyte for this reaction to take place.
  3. Sponsor

    Sponsor Paid Advertisement

  4. nhmaster3015

    nhmaster3015 Master Plumber

    Jul 30, 2008
    The granite state
    Now is a good point to be concerned. Have the gas company or a gas service tech come out and advise you.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    Galvanized, or black, steel gas pipes should NEVER be direct buried in the ground, regardless of whether they are touching copper lines or not. They require special factory applied coatings and specific installation procedures to be used for underground gas lines. In fact, some cities in this area require "cathodic bags" to be attached to underground metal gas lines to protect against failure, even when the approved materials ARE used.
Similar Threads: Copper Galvanized
Forum Title Date
Plumbing Forum, Professional & DIY Advice Dielectric union between copper and galvanized pipe Oct 16, 2016
Plumbing Forum, Professional & DIY Advice Is this guy for real? How not to connect copper to galvanized Mar 18, 2014
Plumbing Forum, Professional & DIY Advice PEX to copper, PEX to galvanized Feb 28, 2014
Plumbing Forum, Professional & DIY Advice transitioning from galvanized to copper Dec 16, 2013
Plumbing Forum, Professional & DIY Advice Copper/Galvanized Corrosion Mar 24, 2010

Share This Page