The Water and Wastewater Companies for Climate Mitigation (WaCCliM) project aims to improve the efficiency of water and wastewater companies in Mexico, Peru, Thailand, and Jordan, reduce their greenhouse gas (GHG) emissions, and improve the carbon balance of the water sector, while maintaining and/or improving service levels. As part of the project, hydraulic modelling software was used to simulate the Cusco, Peru drinking water transmission system and evaluate various scenarios (water loss reduction, pump replacement, and system reconfiguration) and their energy impacts. Results showed the transmission system’s pumping energy could be reduced up to 40 percent depending on the scenario. A holistic view on the total urban water cycle has also helped to identify that a combined effort to conserve water at the end user level, reduce water loss, reuse water, and rainwater harvesting will ultimately make the biggest impact on the transmission system’s energy consumption and GHG emissions, and lead to the most sustainable and resilient urban water management for SEDACUSCO and the City. This study has also demonstrated that water distribution system models can play an invaluable role in water utility climate change mitigation and adaptation planning.