1 / 5Modern-day toilets come with two types of flushes, one is smaller than the other. They are called 'dual flush' toilets but ever wondered why are you given that option? 2 / 5THE CONCEPT OF DUAL FLUSH: The modern-day double flush toilets come with two different types of levers or buttons. One is larger, while the other is smaller and each button is connected to its own exit valve.3 / 5IT IS FOR WATER CONSERVATION: The larger lever is to flush out around 6 to 9 liters of water, whereas the smaller lever is to flush out around 3 to 4.5 liters of water. Clearly, the larger one is to flush solid waste and the smaller one is to flush liquid waste.4 / 5HOW MUCH WATER DO YOU SAVE? It has been calculated that if a household adopts the practice of dual flushing, it can save up to 20,000 liters of water in a year when compared with single flushes. Though the installation may cost you a little more than the normal flush, it is eco-friendly and helps cut down on water bills.5 / 5The dual flush concept is the brainchild of American industrial designer Victor Papanek, proposed by him in his book 'Design for the real world' in 1976. It was first implemented in Australia in 1980.