In irrigation districts, the variable cost tariff have being depended only on the amount of water consumed, and not in the energy and the demand for electric power to supply the water pressure and flow rate recommended by the irrigation system. This way of charge the irrigation water is nonsense, since the less efficient participants subsidized the more efficient ones. Thus, this work proposes that the water tariffs not only consider the amount of water consumed in the month, but also the pressure, since the hydraulic power demand is a function of the product of flow rate times the pressure. The study compared the water cost for participants that consume the same amount monthly for the present situation and the proposed methodology. It was verified, also, the effect of isolated irrigations or simultaneous ones and their implications on the water costs. The results showed that the implementation water tariff that charges the volume of water may reduce the costs for the participants at low pressures up to 66%. On the other hand, high pressure participants may have their water bill increased up to 133%. The simultaneity on the water use also influences its cost due to electrical power demand variation.
water tariff; distribution; irrigated perimeter
