The quality of the fluid we drink is an important determinant of dental and other organ health. The minerals it contains help make up for some of the micronutrients that make up the bones and soft tissues. When the amount, quality and composition of water in the body is changed, the most important processes are disrupted, including the assimilation of nutrients necessary for the normal functioning of all systems. To prevent caries in children the method of water fluoridation is used. Fluoride concentration in water should not exceed 1 mg/l. Because if the above norm of fluoride in the water is exceeded and this water is used to prepare formula and complementary food for the child in the first year of life, such a disease of permanent teeth as “fluorosis” may develop. Its essence is that the calcium in the crystal lattice of the enamel is replaced by fluoride, the enamel becomes more brittle and “brittle”. That’s why it’s so important to strike a middle ground.