An average adult "loose" daily, an average of 2.4 liters of liquid by perspiration. It appears that we should drink 2.4 liters of water daily. But water is not the only source. Water hire and other drinks and juices but also from food.
The exact amount of water needed each of us depends on the diet, gender, physical activity, climatic conditions, state of health, age, and the possible use of drugs.
In special cases such as strenuous exercise or febrile or diarrheal conditions, adequate water intake is very important for replenishing the high fluid loss.
According to the Special Secretariat of Water in Greece, a survey in the water needs are calculated according to the burning of the body. So for each calorie "burned" required 1ml of water and this calculation is applicable to a healthy adult.
The food consumed by an adult daily provide an average 3.4 glasses of water, which means that the rest has to replenish the fluid intake. These fluids may be milk, juices, teas. The coffee and alcoholic drinks cause dehydration, so they do not constitute the best source for the water intake.