Critical infrastructures are the most attractive targets for the elements that threaten the security of societies. Threats on critical infrastructures such as energy, information and communication technology, transportation, health and water are amongst the most vulnerable sectors that national and international institutions are focused on. In this regard, both the United States and the European Union consider water/wastewater infrastructure as one of the most important critical sector. In this study, assessment of the risks for the drinking water infrastructure of İzmir was conducted by using the CARVER method to identify system components that are under higher risk with different scenarios. The results showed that the most critical components of the system were the dam reservoir for the case of an intentional contamination scenario; and, the drinking water treatment plant, water intake structure, pumping stations and dam body for the case of physical and natural threats.