Remaining Useful Life Assessment of Buried Iron Water Mains: Case Studies Using Integrated Diagnostic Methods

Abstract This paper presents two case studies focused on the assessment of remaining useful life (RUL) for aging buried water mains using a multi-disciplinary diagnostic approach. The first case involves a 6-inch cast iron main, over 70 years in service, located in non-corrosive soil (>3,000 Ω-cm; 0 points per American Water Works Association (AWWA) C105). Despite the presence of corrosion-related bacteria and localized internal corrosion at the 6 o’clock position, the pipe remains structurally sound. Magnetic flux mapping, ultrasonic wall thickness, and microstructural analysis yielded an estimated RUL of approximately 85.6 years. The second case examines a 24-inch ductile iron main buried in aggressive gypsum-based soil (