Rainwater Harvesting System (RWHS) for buildings: A mini review on guidelines and potential as alternative water supply in Malaysia

Abstract Malaysia receives an abundance of rain annually (≈ 2400mm/year). The country, however, is not excused from water crises such as floods and shortages. According to the National Water Services Commission (SPAN) data, consumption in year 2021 201 LCD may encounter a shortage crisis if situation improved future. Rainwater harvesting (RWHS) has great potential tackling It can also combat scarcity holistically reduce dependency on treated dam reservoirs. RWHS sustainable alternative tackle with minimal environmental impact. Currently used for non-potable purposes like cleaning, toilet flushing, irrigation. Due nature catchment area, there are several ways which contaminants enter rainwater system compromise quality. Elements topography, weather, pollution sources, have direct impact quality that collected stored. In addition uses, RWH been potable countries Australia Bangladesh, but total number uses still very small. For use, regular monitoring required because it poses health risk due presence chemical, physical, microbiological contaminants. If parameters meet acceptable levels supply, harvested could be drinking many To ensure consistently good quality, essential establish standard operating procedures maintenance schedules based safety plan approaches both household institutional users. This paper aims review existing management guidelines explore technologies buildings across Malaysia.