Throughout this Arroyo, water banking refers to the storage of water underground in natural aquifers for future use. In Arizona, this underground storage is achieved through recharge projects permitted by the Arizona Department of Water Resources (ADWR) through the Underground Storage, Savings and Replenishment Program. When there is a need to use stored water, it is recovered through wells permitted for recovery also by ADWR. While simple in concept, the actual functioning of water banking, recharge, and recovery in Arizona can be very complicated. The purpose of this Arroyo is to describe, in a clear and straight forward way, how water banking, recharge, and recovery actually work.