An approximate yet general approach for describing the overall behavior of water supply systems dominated by carry-over storage is introduced. Generalized relationships among reservoir system storage, yield, reliability, and resilience are introduced for water supply systems fed by autoregressive normal and lognormal annual inflows. Relationships for reservoir system resilience are derived which represent the likelihood that a system will recover from a failure, once a failure has occurred. Monte Carlo experiments document that a two-state Markov model can reproduce the relationships between resilience and reliability for a wide class of water supply systems. A two-state Markov model combined with some existing analytical relationships among storage, reliability, and yield provides a very general theoretical foundation for understanding the trade-offs among reservoir system storage, yield, reliability, and resilience. ¿ American Geophysical Union 1995