The objective of the paper is to evaluate the potential of tank-based rainwater harvesting systems as source control methods to mitigate runoff flow peaks in urban areas. Water balance simulations of the rainwater tanks at the resolution time scale of 1 minute were carried out for this purpose using both high-resolution rainfall series and toilet water demand data from a previous experimental campaign, which involved six experimental households in southern Italy. Simulations show that significant reduction of the flow peak may be obtained with rainwater tanks depending on the tank size and on the household water demand. (C) 2014 The Authors. Published by Elsevier Ltd.