Reusing water is an innovative initiative that has to face the challenge of legitimization. It contradicts the regulatory, normative, perceptual and pragmatic status quo of use.

The public has questions generally for its benefit:

– Being morally stigmatized.

– Conflict with the regulations.

– Be incomprehensible to many users and experts.

We can consider two fundamental ones: a) Irrigation without restrictions, non-drinkable water and b) reuse of drinking water (indirect and direct)

We must also consider four main aspects: The challenges of integrated water management in current social and climatological conditions; The role that water regeneration and reuse is having in integrated management; The similarities between two great territories of Mediterranean climate: Catalonia and California; The valuable experiences that are being experienced in the fifth consecutive year of intense drought in California.

We must take into account the current conception water of the planet that is part of a system: the Water Cycle, the Hydrological Cycle.

This cycle includes surface, underground and "new" (unconventional) sources and the context of a river basin. The environment is a full-fledged user (DMA) and the water system is closely related (nexus) to energy and climate systems. We have finite water resources (nexus energy) to serve the natural environment and a growing population (7.3 billion, 150
W / min; 180,000 p / day …) and consumptions are intensified in urban areas, in a future of inevitable growth that considers:

– An agriculture that proposes to supply us with food.

– Models of climate change that anticipate a greater uncertainty (irregularity) rainfall.

– Average annual reduction of 5% in our territory.

– Greater seasonal and annual irregularity.

We should take into account integrated management since we have strategies to address water consumption with available resources (mitigating hydrological droughts), and we must highlight:

– Preservation and improvement of water sources.
– Saving (conservation) and efficient use of water.
– Regulation and storage of resources: reservoirs (existing and bypass) and aquifers (water banks).
– Exchange and transfers between users (concessionaires): consortiums, mancomunidades, transfers, DCFC.