Growing awareness of water resources' scarcity calls for renewed political intervention as technical solutions can no longer provide viable answers to the issues raised by competing uses of water. Even though Switzerland does not appear to be subject to drought or other scarcity issues, local situation of overuse can arise. This is the case with hydropower production in the Alps, more precisely in canton Valais, where long term contracts (concessions) protect the electric companies' vested rights from newer legal provisions that aim at improving the water based ecosystem through minimum in stream flow standards. This example illustrate some of the difficulties that can appear in the process of regulating water uses (i.e. demand), such as the relevance of both property rights and public policies, the importance of non-water related regulation (in this case electricity/energy policy), or the emergence of new use (ecosystem needs) and the reallocation of water among (pre-existing) competing use(r)s. The proposed communication rests on preliminary results from my ongoing research and consists mainly of a descriptive account of the institutional setting in Switzerland and its possible implication for water regulation and conflict across sectoral limits.