The water infrastructure system is one of the eight key infrastructures that provide essential services to our society. The water distribution system typically consists of multiple subsystems in grid or network patterns. In addition, water network configurations vary based on geographical layout and water sources. Since water subsystems are interconnected, proper functioning of a particular component is highly dependent on other components. An intentional attack on a well-selected set of components can result in catastrophic disruption of water service. This paper discusses the development of a framework that can be used for the design, operation, and maintenance of robust water systems. The framework considers the vulnerabilities of the water network to intentional attacks and evaluates the consequences of such attacks. The paper also examines potential mitigation strategies to either eliminate the risk or to reduce the level of risk of the system in instances of intentional attack. Such an approach can help water infrastructure asset managers to plan and allocate their budgets when security is included as a significant factor in asset management.