Groundwater is a relevant resource in a large part of the Iberian Peninsula and in the Balearic and Canary Islands. The total recharge is about 30 km(3)/yr and about 7 km(3)/yr are used directly. The difference between these two values is flow contributed to the rivers and the sea, with an ecological role and provider of ecological services. The intensive groundwater development started late in the 19th century, with an extraordinary growth between 1950 and 1990. A large fraction of this development was as private domain waters, so this conditions the present situation, in which all waters are in the public domain. This and the development of intensive irrigation in semi-arid climate creates a situation that conditions water planning and requires significant changes in the paradigm to get a sustainable use of water, considering quantity and quality.