AWWA JAW26180

Many utilities do not appreciate the fact that routine breaks of metal water mains often result from deterioration caused by gradual external corrosion. The author outlines the basic terms and conditions of galvanic and electrolytic corrosion, summarizes case studies that illustrate causes of external corrosion of underground metal mains and that describe methods to control external corrosion, and discusses the role of soil in external corrosion. Critical research needs identified include prolonging existing main life, identifying and controlling electrolytic corrosion problems, and evaluating the economics of corrosion control for new mains. Includes 21 references, tables, figures.