A comprehensive investigation of copper pitting corrosion in a drinking water distribution system

Copper pitting is a complicated corrosion process for which exact causes and solutions are often uncertain. This paper presents the findings of a comprehensive investigation of a cold water copper pitting corrosion problem in a drinking water distribution system, including a refined process for preparing exhumed copper pipes for solids analysis. The investigation produced detailed structural, morphological and elemental details of copper pitting that strongly corroborated previous observations and theoretical models, and revealed new findings. For example, cross-sections revealed three components: the cap, characterized by two basic copper sulfate minerals; the cuprite membrane; and the pit containing cuprite crystals, and chloride.