This article deals with materials engineering as it relates to the treatment and supply of drinking water. The authors discuss how materials engineering can expand past traditional uses to rewrite material specifications, coordinate vendor surveillance, provide predictive testing to prevent failures, and consult on new designs. Three case studies on treatment system failures are provided as evidence of the growing value of materials engineering within the water industry. Case study 1 involved failure in treatment chemical storage. Case study 2 investigated failure in filter plant pumps. Case study 3 looked into failure at copper service line connections. Materials engineering as a means of managing infrastructure is also discussed. Includes 5 references.