In anticipation of recent regulatory developments with respect to the application of metallic materials in domestic installations, the chemical reactions during general corrosion of copper pipes were studied in a research project funded by the German Federal Ministry of Education and Research (BMBF) and the German Technical and Scientific Association on Gas and Water (DVGW). A corrosion mechanism was derived which qualitatively explains the observations in stagnation experiments and which serves as the basis to quantitatively model the copper concentration during stagnation. The results of this research provide the scientific background for future studies on the applicability limits of copper, on the influence of water constituents (anions, inhibitors, DOC etc.), and on the optimization of corrosion control strategies.