Seasonal tariffs can be very effective in providing higher incentives for saving water in periods with high scarcity. Increasing-block tariffs, on the other hand, which foresee elevated charges above a certain level can be an effective way of reducing consumption from users with very high demand (WATECO, 2003). In any case, price structures need to be volumetric, with low fixed charges, in order to provide incentives for reducing water consumption. Water metering is usually a precondition for effective pricing systems (Roth, 2001, Lallana et al.,