Rainwater Harvesting System Implementation for Domestic Water Use: The Environment and Financial Benefits

Rainwater harvesting (RWH) system is a technology that focuses on sustainability and supports the sustainable environment development. The implementation of RWH systems provides many environment and financial benefits. Some of the environment benefits of RWH system are as follows: reduce the surface runoff, reduce the burden of soil aquifer, and provide the availability of clean water. This study analyzed the RWH system implementation benefits in both environment and financial sides. The financial benefits of RWH system implementation are calculated based on rainwater that can be used to replace the need for clean water. The environment benefits are defined by the reduction in main water tap use and the reduction in generated roof runoff volume. This study used a simple RWH system that uses the roof as a catchment area, the pipeline as a distribution system, and the tank as a storage system. The water use is for domestic potable and nonpotable for a household with up to four occupants in Bandung. The catchment area is taken up to 70 m². A water balance model for various scenarios was developed to calculate the algorithm of the system. The costs taken in RWH system include the construction, installation, maintenance, and operational costs. The analysis shows that the implementation of RWH systems provides advantages over the use of conventional systems. It can save clean water usage up to 54.92% and provides runoff reduction up to 71.53%. RWH system requires additional costs approximately 0.66% from the value of the house. It was found that it is possible to achieve payback in RWH system implementation under several scenarios.