Berlin Rules on Water Resources

The Berlin Rules on Water Resources is a document adopted by the International Law Association (ILA) to summarize international law customarily applied in modern times to freshwater resources, whether within a nation or crossing international boundaries. Adopted on August 21, 2004, in Berlin, the document supersedes the ILA's earlier "The Helsinki Rules on the Uses of the Waters of International Rivers", which was limited in its scope to international drainage basins and aquifers connected to them.

Source: Wikipedia — Berlin Rules on Water Resources (CC BY-SA 4.0)