FIELD: treatment of water. SUBSTANCE: invention relates to equipment for electrocoagulation purification of water from hardness salts and other impurities. The electrocoagulator in the form of an electrode unit comprises a body with a lower bottom, side walls, insulating pads, an upper flange, and a removable cover, unipolar electrodes, current leads to the electrodes, input and output fittings. An anode in the form of a crosswise support, the lateral ribs whereof act as spacer guides of the filtering partition, is therein coaxially located inside the vertical cylindrical body. A source water inlet pipe is located in the lower flange connection with the insulating pad, and an outlet pipe is located in the upper part of the body, wherein the body acts as the cathode. EFFECT: use of the invention allows for an increase in the efficiency of electric treatment of mine acidic waters with an adjustment of the pH value.