Effective management of scarce water resources requires a systems approach. A quantitative framework, termed the chain of efficiencies concept, was described in the previous meeting of WASAMED and proposed for use in the analysis of water use efficiency of production systems. Starting at the source of water, a cascade of events leads to the final production of crops or animal products at the expense of water. These events are mostly sequential, with each process step in the sequence having its own efficiency of output per unit of input. It turned out that the overall efficiency of a whole process is the product of the efficiencies of each sequential step. That is, efficiencies of individual process steps are multiplicative in determining the overall efficiency. Thus, improvement in any one of the efficiency steps has equal effect in improving the overall efficiency, and the overall improvement is more than the sum of the individual improvements. This principle provides a simple and quantitative means to optimize the allocation of limited resources in improving water use efficiency. In this paper some of the key features of the chain of efficiencies concept are reviewed and some parts of the crop production systems are examined in terms of the framework. Some experimental data are given to illustrate the factors that impact some of the step efficiencies. Included in the consideration are some specialized water management techniques.