P roviding safe and sufficient water to the public is a major and also international challenge. To tackle this challenge and to operate our urban water infrastructure in the most efficient way, instrumentation, control and automation (ICA) is a key aspect of process operation and design. In this editorial, the ICA Specialist Group of the International Water Association (IWA) sheds some light on the current practice and limitations of ICA in different sub-domains of the urban water system, followed by some personal perspectives. Current status of ICA Instrumentation, control and automation (ICA) is nowadays a recognised area of technology in urban water management. The progress made over the last decades has been made possible by advances in instrumentation technology (sensors and actuators) and the development of advanced mathematical models and their implementation in commercial simulators, accompanied by an exponential increase in the available computing power (Olsson et al., 2005). Starting from hydraulic sewer models and a focus on the activated sludge processes at WWTPs, the model boundaries are more and more expanded from unit processes to system- wide perspectives: sewer models now include water quality parameters, WWT whole plant models (such as the Benchmark Simulation Model No. 2 (BSM2), see Gernaey et al., in press) are used in daily engineering practice (Rieger et al., 2010) and river water quality modelling is finding its way into practice as well. This trend will allow an integrated view at the whole urban water cycle and will certainly lead to a better understanding of these systems and consequently to a more efficient use of public infrastructure. Wastewater treatment plants The degree to which ICA is installed at current wastewater treatment plants (WWTPs) depends on the geographic region, effluent requirements, the complexity of plant design, and the size of the plant. The increased research interest for controlling WWTPs in the last 20 years, as reflected by the number of related publications and citations found in Web of Science (Figure 1 – see page 34) has resulted in an increasing amount of control implementations in practice. It can reasonably be expected that the need for ICA will further increase in the near future as i) the effluent standards become more stringent and ii) the pressure on public budgets makes it necessary to make our infrastructure more efficient. The most powerful control handle at WWTPs is aeration, which contributes for up to 60% to the total energy consumption of a plant. Whereas a worldwide majority of plants are still operated with no control (fixed airflow), most plants in Europe apply at least basic DO control. A clear trend is seen towards multi-DO probe control systems or even cascade control configurations in which the airflow is adjusted based on ammonia or nitrate probes. Despite a wide range of monitoring techniques, related to multiple control variables, current WWTPs still suffer from limited controllability. This is caused by (i) static design for maximum load and worst case conditions or (ii) through a lack of actuators (valves, pumps or compressors) with sufficient control power. Another topic still unresolved is the monitoring of the data quality. Automatic data evaluation is a prerequisite for robust and fault tolerant control and is getting more and more attention in research. Sewers – storm tanks ICA in sewer systems is often confronted with difficult conditions caused by a high variability in flow rate and pollutant concentrations, a corrosive atmosphere, explosion risk, deposition and erosion of sediments and a general problem of accessibility. All this puts high demands on the used sensors and actuators, the applied control algorithm and the required strategy to avoid control disasters caused by sensor failure. In contrast to WWTPs, ICA in sewer systems predominantly deals with flow rates and water levels so far. Although still limitations exist to provide robust and reliable online measurements that can be used for more advanced control, new sensor technologies and measurement methods seem Instrumentation, control and automation in urban water management: state-of-the-art and future perspectives water&sewerage journal Features 33 Eveline Volcke, Department of Biosystems Engineering, Ghent University, Ghent, Belgium Dirk Muschalla, ITWH – Institute for Technical and Scientific Hydrology, Hannover, Germany Jean-Philippe Steyer, INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Narbonne, France Leiv Rieger, EnviroSim Associates Ltd, McMaster Innovation Park, Hamilton, Ontario, Canada