‘ Rainwater Harvesting is considered as a low cost and eco-friendly technique of preserving water resources.’, Justify. Rain water harvesting is a method to capture and store rainwater for various uses. It is also used to recharge groundwater aquifers. It is a low cost and ecofriendly technique for preserving every drop of water by guiding the rain water to bore well, pits and wells. Rainwater harvesting increases water availability, check the declining ground water table, improves the quality of groundwater through dilution of contaminants like fluorides and nitrates, prevents soil erosion, and flooding and arrests salt water intrusion in coastal areas if used to recharge aquifers