The chapter presents experimental data, published in numerous source materials and reviews, on the mutual solubility of water in hydrocarbons and hydrocarbons in water, relationship of water solubility in hydrocarbons depending on the structure of the organic compound molecule and the change of solubility as a function of temperature. Possibilities of water solubilization, dissolved and dispersed in hydrocarbons, their mixtures as well as fractions, and petroleum products were analyzed. With the help of turbidimetric measurements, surfactants and mixtures of surfactants with the highest water solubilization capacity in fuels were selected. Different methods of dewatering of distillate fractions, gasolines, and diesel fuels with the use of coalescing partitions were investigated. A number of barrier materials, methods of modifying the structure of the partition, and the hydrophilicity of glass fibers were tested, obtaining very good results in industrial applications.