Optimisation of fresh water consumption in continuous water networks (WN) leads to the optimal solutions but not resistant to many kinds of changes and disturbances of process parameters. In cases where it is possible to predict the process changes and the extent disturbances of water parameters, from a practical and economic point of view flexible water network (FWN) should be designed. In this work, solved problem of optimal design of FWN containing the source and sinks of process water as well as regeneration processes. Taken into account both the variation of the concentration of pollution in the regenerated water and periodic downtimes of selected sources and sinks. To solve the problem algorithmic method based on the superstructure optimisation has been applied. This method uses theorem of corner points. FWN obtained with the method is characterized by minimal consumption of fresh water in all possible production situations. FWN also has minimum number of pipelines which has large impact on the investment cost. The method also gives insight into the possible flow rate in each pipeline. This information is fundamental for network designer to proper select of pipes diameters and ancillary equipment.
