Water authorities in countries facing water shortage problems are implementing intermittent water supply (IWS) policies, as a measure to conserve and control their national water resources. Implementation of such measures affects the behaviour of the water pipe systems during the operation stage. The research work presented herein presents a model simulating the behaviour of urban water distribution networks (WDNs) under normal operating conditions, as well as during a period of IWS operations. The modelling and analysis, based on an eight-year dataset (2003–2010) from a local Water Board, takes into account information related to breakage incidents within the WDN as well as external factors to perform vulnerability assessment of the pipe network. The results of the performed survival and cluster analysis show that during the implementation period of IWS operations, and right after that period, there is a significant increase in the deterioration rate of the affected network. Further, there is a change in the comparative importance of the factors affecting the network condition and their contribution to the WDN vulnerability.