During the last decade, it has been acknowledged that, at national level, the availability of water is a trade-off between its temporary and spatial distribution as well as contamination problems. This situation has urged the Mexican Government to revise the plans and programs for the integrated management of hydric resources by analysing the institutional system, the legal frame and its effectiveness. Within this context, an essential aspect is to ensure the ordering of the uses and exploitation of water resources.
This paper shows that a revision of the effectiveness and applicability of the current water standards and laws is essential to satisfy the demands, and to have control over the different uses of water (drinking water for human consumption, the use of water for agricultural, municipal, industrial related activities and other purposes). Therefore, in this work, a redefinition of the Ecological Criteria of Water Quality has been proposed. The proposal establishes the Quality Criteria under a new perspective, wherein the set of parameters and their values constitute the goal of quality, in the sense that any type of water with such characteristics or better ones, cannot only be used as it is, but constitutes the most suitable water for such use.