Water is frequently considered both as a social category and as an economic good. On 28 July 2008, through Resolution 64/292, the United Nations General Assembly explicitly recognised the human right to water and sanitation, and acknowledged that clean drinking water and sanitation are essential for the realisation of all human rights. In November 2002, The Committee for Economic, Social and Cultural Rights adopted General Comment No. 15 on the right to water. Article I.1 states that “The human right to water is indispensable for leading a life in human dignity. It is a prerequisite for the realization of other human rights.”  The same Comment also defined the right to water as the right of everyone to sufficient, safe, acceptable and physically accessible and affordable water for personal or domestic uses.

Such a definition leads to another principle applied in water supply, the principle of equity and equality. This principle causes the partial application of the previously mentioned principle “consumer pays”, since the objective is to assure water under equal conditions for the entire population.