Mohan Munasinghe, the co-winner of the Nobel Peace Prize with Al Gore some years ago, was in Barcelona on wednesday to give a very interesting lecture at the Water Economics Forum. He explained with detail why it is important that we try to combine economic growth with environmental protection and social concerns. He also addressed the specific issues of the pressure on water resources given by demographics and climate change. One idea he emphasized a lot was the urgency and necessity of striking the right balance between subsidiarity and integration in water policies. Climate change calls for enhanced policies of infrastructure investment and efficiency, coordinated with income distribution so that the poorest are protected from the price increases that are often needed to achieve these efficient changes. The levels of government that are closer to the citizens, as well as local communities themselves, have the information and the ability to manage policies of good resource use. At the same time, water is a scarce resource that is unequally distributed over time and space, which makes it necessary to share it in a coordinated way. Many experiences show that this is challenging to say the least. But unless we improve the balance between subsidiarity and integration of water policies it is going to be very difficult to develop the effective water policies that are necessary. In my participation in a roundtable of the same event, I tried to apply the lessons of Mohan Munasinghe to the case of Spain. The success of water policies in Spain clearly depends on this balance. Spain is integrated in the European Union and the euro zone, and has no plans of withdrawing. On the contrary, there is a political and public consensus on staying, and on participating in the core of the Union with those that are willing to integrate even more. And Spain is also a very decentralized country, with 17 powerful regions, more than 8000 municipalities and two metropolitan areas (Madrid and Barcelona) with justified international ambitions. Our water policies will remain very decentralized, but there is scope for improving how this decentralization works, and there is scope for achieving better inter-regional coordination and better coordination with European-wide policies and iniciatives. I suggested that at the Spanish level there is perhaps scope for a federal water regulator, not one that takes away powers from lower government levels, but one that provides a forum for agreements between users and territories, and that makes a systematic effort of information collection and difusion of good regulatory practices and standards.