Water consumption in residential parts of urban areas is just one part of the water management problems. Contemporary potable water management is not sustainable whereas we use potable water for flushing toilets, irrigation or washing vehicles. The appropriate solution is to substitute potable water with rainwater for some purposes and this water source is considered sustainable. Submitted paper presents risk assessment using risk analysis of the rainwater harvesting (RWH) system. This paper does not deal with the system in details but informs about the selected approach of the evaluation methodology verified by analytical hierarchy process. (C) 2014 The Authors. Published by Elsevier Ltd.