This technical committee report provides a state-of-the-art overview of the corrosion and corrosion protection activities related to residential and small commercial water heaters used in potable water systems. It is beyond the scope of this report to address all corrosion factors for all residential and small commercial water heaters on a global basis. An effort has been made, however, to describe the most prevalent water heaters used today, with accompanying information on operation and maintenance. This report is also intended as a technical and application resource for the broad range of persons involved with the manufacture, distribution, and installation of water heaters.This report is not intended as a guide for improved or altered manufacturing procedures for water heaters.