Grey water refers to the reuse of water drained from baths, showers, washing machines, and sinks (household wastewater excluding toilet wastes) for irrigation and other water conservation applications.
Building Layout Water harvested in the building with a flat terrace area of 60 sq .m The average annual rainfall in Chennai is approximately 1300mm. In simple terms, this means that if all the rain that falls on the terrace is retained, then in one year there will be rain water on the terrace floor to a height of 1300mm. Amount of water required per day ---20X135 = 2700L Water reused [GREY WATER ---20X63 =1260 Hence the water harvested is insufficient and needs more of water management systems Area x Height of Rainfall 60 sq. m. x 1.30 m :78 cu. m. (78,000 liters) Volume of rainfall over the Terrace Assuming that 90% of the total rainfall is effectively harvested. Volume of water harvested = 78000x0.9 = 70200 liters That means ( 70200 / 365 ~ ) 192 liters of water per day will be available for the household. Water required per day 72L/PERSON portable water :1.30m (1300 mm) Height of rainfall :60 sq. m. Area of Terrace