The author gratefully acknowledges the extensive contributions of all of the writers of the AWWA publication Corrosion Control for Operators , the AWWARF/DVGWForschungsstelle/TZW manuals Internal Corrosion of Water Distribution Systems , and the late Dr. T.E.Larson, whose works were heavily cited and directly included in this chapter. The author is also indebted to the late Dr. Heinrich Sontheimer for inspiration for much of the copper research, to Dr. Marc Edwards for many interesting ideas and discussion, and to Dr. Ray Letterman, Dr. John Ferguson, and Peter Karalekas, Jr., for their herculean efforts in reviewing the draft and providing very helpful criticisms.