This paper addresses the issue of contaminated water evacuation as part of the response process in cases of intentional or accidental contamination of drinking water distribution systems (DWDSs). Following a previous study which addressed contaminant isolation, an original flushing procedure (FP) is introduced. Through a heuristic set of rules, the FP defines unidirectional flushing (UDF) strategies in a safe, structured, and efficient manner. In addition to the rather theoretical considerations related to hydraulics modeling, the FP also takes into account the operational issues of UDF implementation. Compared to other similar studies, the latter aspect establishes the main contribution of this paper. The FP has been applied to two real-world networks and application of the heuristic rules is demonstrated with the aid of a detailed example. General results suggest possible improvements to existing network configurations and to the design of projected networks to better support contamination response plan...