But here was a substance – in liquid form without which no life on earth would be possible. They say 60 per cent of our bodies are made of water, over 70 per cent of our brains and hearts are water and 80 per cent of our blood. AdvertisementEvery form of life is dependent on water, from microscopic plankton, plants, to giant redwoods, bacteria, insects, reptiles, amphibians, fish and mammals. Though only 3 per cent of the world’s water is ‘fresh’ (and so potable), it seems enough. A lake at sunset (Ranjit Lal) A lake at sunset (Ranjit Lal)Sadly, our treatment of this magic elixir beggars belief.