The content of iodide ions in fresh waters of the Mountain Crimea has been studied. Atmospheric precipitation is the main source of iodine in the groundwater of the Quaternary aquifer, in the waters of the Lower and Upper Cretaceous aquifers, as well as in the waters of the weathered volcanic-sedimentary sediments of Karadag (J2b). There is a small degree of iodine deficiency here, since the concentration of iodine does not reach the lower limit of the standard of physiological usefulness of drinking water. The maximum concentrations of iodide ions are associated with the area of melange.