"Bangalore receives around 900-1000mm of rainfall except for these very drought years," said Mr Shivakumar, whose work involves the field of renewable energy and rainwater harvesting. The amount, he says, is enough to collect 2.3 lakh litres of water a year. But 2.3 lakh liters is far more than an average family of four uses. Planned properly, tanks can be built into a standard 40/60 feet plot to store more than what a small family needs.
Explaining the rainfall pattern of the city, he said, there is 90-100 dry days between two successive rains in Bangalore. "Based on that calculation, we have a storage capacity for 45000 litres... effectively we need only around 40,000 litres - 400 liters a day for 100 days. But we have 45,000 litres for emergency."
The use of water, though, is careful, he said. Recycling plays a big part -- like collecting water from the kitchen sink in a can outside the kitchen to using water from the washing machine to flush toilets.
The water harvesting system is simple - water from the sloping roof is collected n underground tanks, where the purification process happens.
It is a family effort, said Mr Sivakumar - and his wife of 28 years, Suma, and his son, Anoop and daughter in law, Vamika, play their part as water conservation becomes a way of life for them.