Selection of the proper piping material is a critical aspect of wastewater treatment system design, and many factors go into the selection of piping used for industrial water treatment systems. These factors include temperature, pressure, chemical compatibility, and economics. This presentation is designed to give operators a better understanding of what goes into the selection process of piping used in wastewater treatment systems. A brief history of the development of modern materials, common modern piping materials, proper fitting selection, and parameters affecting material selection will be covered.