The results of studies in electrochemical softening of water in a diaphragm electrolyzer with inert anodes and a porous diaphragm were presented. It was shown that the most significant degree of softening of water at the lowest current and electric power consumptions was observed when water was fed to the anode chambers and moved in parallel flows in the electrode chambers. The total hardness of natural water was reduced to 1.4–1.6 mmole/dm 3 , alkalinity to 3.8–4.3 mmole/dm 3 , pH by 0.3–0.6 and acidity practically did not change. The recommended process scheme for water softening involves parallel movement of catholyte and anolyte streams in the electrolyzer at a ratio of their consumptions (7–8):(3–2) and their separate extraction from the electrode chambers. Catholyte is filtered to remove insoluble hardness salts and mixed with anolyte. The degree of water softening is regulated only by changing the strength of direct current applied to the electrodes. The technology makes it possible to completely abandon the use of chemical reagents, simultaneously stabilize and disinfect softened water and avoid secondary contamination of water with chemicals. The design of an industrial monopolar electrolyzer with an inactive diaphragm for electrochemical change of pH and Eh was developed. The electrolyzer features a solid anode and a perforated cathode or perforated electrodes closely pressed against the diaphragm. The softening technology is advisable to use for local water preparation for production operations and before softening hard water with ion-exchange filters or electrodialyzers. The developed technology of water softening and purification has been introduced at a number of enterprises in Slovakia and Ukraine, in particular, for industrial water treatment in galvanic plants and flour mills.