Implications of Future Water Supply Sources for Energy Demands describes the Water-Energy Simulator (WESim), an easy-to-use analytical tool for evaluating the energy and greenhouse gas (GHG) implications of water management decisions. In this report, energy is considered for (1) source water extraction, (2) water conveyance, (3) water treatment, (4) water distribution, (5) wastewater collection, and (6) wastewater treatment. WESim can include commercial and residential end uses of water and energy requirements for end uses. The report includes case studies utilizing WESim by the Santa Clara Valley Water District and Denver Water.