Wells, depending on their environment, deteriorate at varying rates based on factors such as well design, hydrogeology, operational history, water quality, rehabilitation history, and usage. Understanding all of this can be difficult, but this text provides a method to aid groundwater professionals in assessing and assigning a value to a well's health. The information presented within the book was compiled with an intention to extend the operational lifespan of existing wells, while incorporating valuable information into the design and operation of new well systems. The book should be considered as both a reference to define where a well is in relationship to its functional life cycle as well as a guide to identify when rehabilitation needs to be performed to ensure a long life and reduce operational costs. It is authored by long-time groundwater industry professionals, Thomas M. Hanna, PG, Michael J. Schnieders, PG, PH-GW, and John H. Schnieders, Ph.D., CPC.