A reclaimed water system collects domestic wastewater from washing, sewage and dining halls and sends it on to a treatment plant. After tertiary processing it is sent to a tank for storage and subsequently, via its own piping system, to the various buildings where it is used to flush toilets.
由於輸送管線埋在地下的位置介於自來水（上水）和污水（下水）中間，所以稱「中水」；而「中水供水系統」是將盥洗、廁所、餐廳等生活污水，透過污水下水道收集，送到污水處理廠，經過三級處理後送到中水水塔貯存，再經過中水管線輸送到各建築物做沖廁用水。