Understanding and seeking mechanisms for the evaluation of water is crucial for the implementation of the integrated water resources management. One of the four basic principles adopted by Dublin conference in 1992 is that water has value as an economic good. There is no panacea to use this principle in a real life. The aim of this article is to describe terms necessary for better understanding that water, even renewable natural resource, is the scarce capital, and the water pricing should be derived from the value of this scarce natural resource.