Water is one of the most important nutrients for any living organism. Water do not contain any calorie, it do not have amino acids to build our body. But still water is one of the most important nutrients. Animal body contains more than 70% water. So all animal (including human) needs sufficient water for proper functioning of their body.

How much water intake is required per day for an animal is not fixed. The intake of water depends on body size, level of activity, temperature, humidity, and other factors. The more water loss from the body results more requirement of water intake. Water is excreted from the body in different forms. Common route of water loss from the body are urine, feces, sweating, by exhalation of water vapor in the breath etc.

Normally for a healthy person, it needs 2-4 litres of water intake daily. In 1945, Food and Nutrition Board of the National Research Council recommended an ordinary standard for diverse a person, that is 1 milliliter for each calorie of food.

The recommendation of United States National Research Council is 2.7 liters of water for women and 3.7 liters for men in general. Institute of Medicine recommended 2.2 litres water for women and 3.0 litres water for men. For the pregnant women, the recommended water intake is 2.4 liters and for the breastfeeding women the recommended amount is 3 liters/day. This entire requirement calculated including dietary intakes of water. Normally about 20-25 percent of water intake comes from food and rest of the 75-80 percent comes from directly drinking of water and other liquid food like beverages, milk etc.

I recently heard a report on the news that everyone requires a different intake and that some people only need one glass of water a day and others need around five. The standard once said that you have to drink around eight glasses of water a day per day to be healthy but this seems to not be true. No one really ever drinks that much water unless they have made a habit out of it. There is a source of nutrients and water in so many other things you consume that it sometimes is not necessary to drink all that much. I pretty much drink soda for the day and very little water but I still live a relatively healthy life.