The concept couldn’t be simpler. Instead of letting rainwater from the roof and paved areas around the building run to waste, it is collected, filtered and reused as a substitute for treated mains water in non-critical applications. Clearly, water captured in this way cannot be used for drinking, bathing, showering or where there is any possibility of accidental ingestion However, captured rainwater is perfectly suited for general cleaning, toilets, laundry and watering plants. In fact, the absence of chemical additives and retention of natural properties is a positive benefit to plants.