Abstract: There is proposed a water treatment method by causing the water to be pured to flow through a first and a second compartments arranged in succession in an electrolysis cell divided by a permeable membrane into said first and second compartments. Each of the compartments accomodates an electrode, one of them being an anode, and the other--a cathode. Direct electric current is then passed through the water between the anode and the cathode, the current value being determined from the following equation:I=K.times.(C).sup.1/4 .times.Q,whereinI is the current amperage (A),C is the feed water mineralization equal to 0.1-1.5 g/l,Q is the water flow rate (1/hour), ##EQU1## the I/Q ratio being comprised within from about 110 to about 220 Coulomb/liter. The water is caused to flow successively from the anode compartment towards the cathode compartment. Once the water is discharged from the cathode compartment, it is subjected to filtering by passing the water through a bed of a porous carbonaceous material.