Water is indispensable for both life and agriculture. Considering fresh water alone, 77.2% of it is to be found in the polar ice caps and the glaciers, while groundwater accounts for 22.4%, and lakes and rivers for 0.36%. Groundwater is therefore vital for human life. It also gives rise to specific legal problems, which often extend well beyond national boundaries. This is the question that the present study sets out to analyse, in as complete and exhaustive a way as possible.