The physico-chemistry of biofilm-mediated pitting corrosion of copper pipe supplying potable water.

Copper is a generally robust material that has beneficial properties to reduce biofilm formation and pathogen colonisation of pipes supplying potable water. However, a rare pitting corrosion can occur in soft, poorly buffered waters that can lead to pipe failure. This has been shown to be mediated by a copper-tolerant biofilm whose physical and chemical heterogeneity can establish microenvironments for corrosion potentials, causing micro pits that eventually coalesce into large perforations through the pipe wall. Control of the biofilm, for example through reduced cold water or elevated hot water temperatures, can suppress this corrosion phenomenon.