Demand-response is a scheme in which electricity suppliers and consumers collaborate for smarter usage of electricity aiming to mitigate the gap between supply and demand. It makes electricity consumers receive incentives through curtailing or increasing power demand during a certain period subject to request from the power infrastructure. Water utilities, as heavy electricity consumers, could participate in the scheme through shifting power demand by modifying pump operation schedule, utilizing reservoirs' buffering stock capability. We developed a conveyance/transmission pump scheduling algorithm to be applied in the scheme that requires a quick modification of pumping schedule to respond to a request. In addition, we made test bedding through a simulation approach utilizing actual data from Osaka Water Supply Authority to show the scheme's potential for waterworks and the effectiveness of the algorithm.