Sustainability of water resources is often gauged as the gap between supply and projections of demand. This static view, however, is insufficient to judge the ability of a system to cope with uncertainty and variability, and does not monitor progress towards sustainability. That is, sustainability should be viewed as a process, not a goal. Commonly used performance indicators such as reliability, resiliency, and vulnerability are some aspects of the concept of sustainability. They are easy to use, can monitor trends, and can be adapted to account for changes in physical and social systems that affect the concept of sustainability. The case of Israel is considered as illustration. The water system and agricultural production dependent on it have exhibited high vulnerability and low resilience and reliability, in spite of change to the master water plan at the beginning of the 1990s.