A waste management system plays a leading role in the capacity of an area to restart after flooding, as their impact on post-crisis management can be very considerable. Improving resilience, i.e. enabling it to maintain or recover acceptable operating levels after flooding is primordial. To achieve this, we must understand how the system works for bringing any potential dysfunctions to light and taking preventive measures. Functional analysis has been used for understanding the complexity of this type of system. The purpose of this article is to show the interest behind this type of method and the limits in its use for improving resilience of waste management system as well as other urban technical systems1, by means of theoretical modelling and its application on a study site. © 2012 Author(s). CC Attribution 3.0 License.