The sustainability of rainwater harvesting for supplying domestic water demand in Yogyakarta City

Yogyakarta city has a problem of water resources management along with the rapid development in this region. Rainwater harvesting (RWH) can be an alternative choice in urban water resources management. This study aims to determine the best RWH scenario as a sustainable water supply to meet domestic water demand in Yogyakarta City. The method used is the Sustainability Index with 3 parameters including reliability, resilience and vulnerability. Each parameter is a derivative of a water balance simulation of the RWH system using the data range in the period 2006–2015. This study compares the percentage of roof usage in the RWH system and the level of domestic water demand. The results of this study indicate that the RWH scenario by utilizing 50 %–75 % of the roof area can be ideally meet up to 80 % of domestic water needs in Yogyakarta City. RWH scenario with 100 % roof usage can meet all domestic water needs well. This study shows that the RWH system can have a positive impact on the management and sustainability of water resources in Yogyakarta City.