SAFEGE and CAIL designed and developed a complete small water distribution network management system. The product is used in the Northern Parisian District. The user requirements were that the system was simple to install and operate, and that little data was required to operate it. Costs of installation and development had to be kept low. The system's optimization model, when integrated into a SCADA system, operates automatically; it is failsafe and provides useful commands for optimum reservoir level management, such as startup and shutdown of pumps and opening and closing of valves. In case of emergency or faulty operation during the optimization process, it is replaced by standard control commands. Under these conditions, control switches back to the SCADA system. The network editing model provides an object oriented, user friendly graphic environment for modeling and simplification of the model. Optimization is not only linked to energy costs but also to power supply contract rates and energy consumed per flow unit for each pumping unit. An optimization calculation is executed every 15 minutes and includes calculation of time steps, linear optimization, and discrete optimization. A memory database allows for easy access to data.