new Unit tanks colour drains Filter method device terrace purpose flat RCC benefits turbidity courtyard components irrigation First Flush open ground Water pipes sloping roof contaminants cleaner water Transportation microorganisms catchment area allegianceindia laundry washing toilet flushing garden watering roof catchments storage systems household needs Application Areas initial rainwater existing buildings UV-resistant pipes Allegiance Enterprise Allegiance Water Management artificial recharge techniques Non-potable household activities sub-surface groundwater reservoirs Rooftop rainwater harvesting systems