Sponge city is a research project focused on water management in Greater Jakarta, from upstream to downstream. The study identified patterns of rainwater runoff related to the density of development at various points along the river basin. Before extensive development, most of the water would infiltrate the ground, resulting in relatively small volumes of runoff into the rivers. In areas with high density, the runoff volume increases significantly. What if development could proceed while maintaining infiltration behavior and retaining as much rainwater as possible on each plot? This research outlines various strategies tailored to different areas, each with unique characteristics.