Public health surveys spanning decades have studied the nutritional status and its association with the health promotion and disease prevention․ Water is a nutritional component. Water is essential for digestion, circulation of nutrients, movement of substances across cell membranes, metabolism, and regulation of intracellular-extracellular concentration. These processes are optimized by the stringent defense of the central nervous system of body, water and fluid concentration. Recent scientific studies presented in this article show that low volume water intake is associated with adverse health outcomes. According to these studies, low daily water consumption activates the body’s homeostatic mechanisms with the participation of AVP to maintain the water-osmotic balance, contributes to the increased risk of developing chronic diseases. In different countries 25-33% of all adult population intakes less than 1.5 L of water (total intake) per day, which is significantly less than adequate water intake levels. To ensure optimal hydration, it is proposed that the optimal total water intake for healthy adults in temperate climates with mild to moderate physical activity should be from 2.5 to 3.5 liters per day․ Studies provide convincing evidence of the need for adequate fluid intake as a safe, simple preventive measure against various diseases.