Rainwater harvesting is the crying need of the day. It is said that if the Third World War is to be fought, it will be fought for water. The huge quantity of rainwater goes down the drain every year. Every home, every village, every city should have a rainwater harvesting system. It saves us from floods. It saves bays, seas and oceans from overflowing. It maintains the groundwater level. In the desert area, it makes available the precious water round the year. It can be used for irrigation, too. Thus, the harvesting of rainwater is the immediate need of the hour.