Lima faces multiple challenges such as a growing urban population, limited and polluted water supply and unsanitary housing. Positioned in an area of limited precipitation, the city is dependent on underground and surface water delivered from the Andes Mountains by rivers. These rivers are heavily polluted and are seasonally variable, and will be subjected to climate change in the future. Given the water scarcity and underdeveloped wastewater treatment, Lima had collaborated with stakeholders to impact national legislation on wastewater reuse and to establish a demonstration project: using treated wastewater for a multifunctional city Eco-Park. This legislation allowing for wastewater reuse for irrigation of urban green spaces has opened the way for further applications with multiple benefits.