Historically, global water law has developed in fragments. The fragmented nature of water law mainly originates from the fact that water can be seen as an economic, ecological and social unit (horizontal fragmentation). Within the clusters that these units constitute, water law is also seen as fragmented, given that a particular cluster is composed of different levels (vertical fragmentation). This article will scrutinise the social justice cluster, or the right to water, and examine whether and to what extent vertical fragmentation in water law leads to divergent approaches among the different levels, while placing the discussion within the general context of fragmentation in international law. For that purpose the elaboration of the human right to water by the Committee on Economic, Social and Cultural Rights, functioning at the international level, will be compared with the practice of the European Court of Human Rights (ECTHR), a regional court.