**5. Concluding remarks**

Since flow conditions inevitably change, pressure transient analysis is a fundamental part of WSS design and a careful analysis may contribute significantly to the reduction of water losses from these systems. It is shown that pressure transient analyses are indispensable in most stages of the life cycle of a water system. Section 2 shows that existing standards focus on a certain maximum allowable incidental pressure, but also emphasises that other evalua‐ tion criteria should be part of the surge analysis, including minimum pressures, component specific criteria and maximum allowable shock pressures. It is recommended that pressure shocks due to cavity collapse, air-release or undamped check valve closure should never ex‐ ceed 50% of the design pressure. The main contributions of this paper, as compared to exist‐ ing pressure transient design guidelines, include an overview of emergency scenarios and normal operating procedures to be considered, as well as the integrated design of control systems and anti-surge devices. These will lead to a safe, cost-effective, robust, energy-effi‐ cient and low-leaking water system.
