Effectively managing valves as an asset can have a significant impact both for the water utility and the customer. This revised manual covers valve selection and installation as well as the importance of location, condition, and frequency of operation. The updated figures show commonly used valves and their components, including: globe; butterfly; plug; ball; cone; and gate. Special-use valves are also discussed, but the intent here is only to introduce their availability and applications. The authors incorporate the latest methodologies and technologies for handling, inspecting, shipping, and storing valves and their associated parts. A brief history of valves and an overview of the theory and flow characteristics of valves provides context. Valves are an indispensable component of the water distribution system; they can regulate, modulate or isolate. This manual provides essential information for water operators, technicians, and engineers on this powerful appurtenance.