The sustainability of water resources is a critical factor in the development and the ongoing viability of healthy communities. Determining, with great certainty, that systems can be developed to ensure that sustainability is a great challenge to water resource systems engineers. The greatest design, planning, and management challenges lie in the engineer's limited ability to quantify potential future conditions. This study explores the utility of fuzzy set theory in the field of water resource systems reliability analysis and proposes three new fuzzy reliability measures: (1) a combined reliability-vulnerability index, (2) a robustness index, and (3) a resiliency index. These measures were evaluated using two simple hypothetical case studies of water supply systems. The indices suggested are able to handle different fuzzy representations and different system conditions.