Estimating Rainwater Harvesting Potential for Mexico City Metropolitan Area Using System Dynamic Modeling

Water scarcity is a growing concern in the Mexico City Metropolitan Area (MCMA) due to increasing population, rising demand, and over-extraction of groundwater. Rainwater harvesting (RWH) presents a potential supplementary water source to reduce reliance on municipal supplies and mitigate groundwater depletion. However, large-scale implementation faces challenges, including disparities in water access, infrastructure limitations, and the impacts of climate change. This study estimates the potential of RWH in MCMA using system dynamics modeling, incorporating population growth projections, storage capacities of 2,500L, 5,000L, and 10,000L per household, and climate change scenarios SSP2-4.5 and SSP5-8.5 to analyze future precipitation variability. Results indicate that as population grows, RWH potential increases due to larger rooftop areas available for rainwater capture. Water savings range from 11% to 29%, with higher efficiency observed during the wet season. However, significant disparities exist among marginalization zones (1–5), with more vulnerable communities facing greater difficulties in implementing RWH systems. Climate change projections reveal variations in future precipitation patterns, emphasizing the need for adaptive and integrated water management strategies. Climate change projections reveal variations in future precipitation patterns, emphasizing the need for adaptive and integrated water management strategies. While RWH can help reduce municipal water demand and groundwater depletion, its success depends on policy alignment, infrastructure investment, and public engagement. Addressing water quality concerns, maintenance, and public acceptance is key to a large-scale adoption. Results suggest that RWH, when paired with supportive policies and infrastructure, enhances resilience and reduces municipal costs. RWH offers a promising strategy for urban water management in MCMA, its long-term and large-scale success for water-sustainability.