Method of chlorinating drinking water on a ship, in particular a passenger ship, which ship is equipped with a drinking water production and distribution system comprising a recirculation distribution network and a device for injecting at a predetermined injection point into the distribution network at least one chlorine compound capable of generating free chlorine in water, said chlorinating method comprising a step a) of chlorination, in which said at least one chlorine compound is injected into circulation at the predetermined injection point in order to keep the distribution network aseptic, and being characterised in that it comprises the following operative steps: - a step b) of fixing a regimen set point for the concentration of free chlorine at the injection point, comprised between 0.4 and 1.2 mg/l; - a step c) of monitoring the concentration of free chlorine at or near the injection point by means of at least a first detection probe positioned therein; - a step d) of continuously monitoring the concentration of free chlorine at the furthest point of the distribution network from the injection point by means of at least a second detection probe positioned therein; and in that the injection step a) comprises a sub-step a1) of regimen chlorination in which the injection of the chlorine compound in the distribution network is conducted so as to maintain the concentration of free chlorine in the distribution network at the injection point at said regimen set-point, said regimen chlorination sub-step a1) being performed if the second probe does not detect variations in the concentration of free chlorine at the furthest point with respect to the regimen set point or if the second probe detects variations in concentration with respect to said regimen set point having entity lower than a predetermined safety limit (diff1) and/or duration lower than a predetermined safety time limit (Δt1), drops in the concentration of free chlorine in the furthest point with respect to the regimen set point being directly attributable to the presence of biological material in said distribution network and being suitable to use as a trigger condition for actions of temporary raise of the level of chlorination at the injection point with respect to said regimen set point. - a step b) of fixing a regimen set point for the concentration of free chlorine at the injection point, comprised between 0.4 and 1.2 mg/l; - a step c) of monitoring the concentration of free chlorine at or near the injection point by means of at least a first detection probe positioned therein; - a step d) of continuously monitoring the concentration of free chlorine at the furthest point of the distribution network from the injection point by means of at least a second detection probe positioned therein; and in that the injection step a) comprises a sub-step a1) of regimen chlorination in which the injection of the chlorine compound in the distribution network is conducted so as to maintain the concentration of free chlorine in the distribution network at the injection point at said regimen set-point, said regimen chlorination sub-step a1) being performed if the second probe does not detect variations in the concentration of free chlorine at the furthest point with respect to the regimen set point or if the second probe detects variations in concentration with respect to said regimen set point having entity lower than a predetermined safety limit (diff1) and/or duration lower than a predetermined safety time limit (Δt1), drops in the concentration of free chlorine in the furthest point with respect to the regimen set point being directly attributable to the presence of biological material in said distribution network and being suitable to use as a trigger condition for actions of temporary raise of the level of chlorination at the injection point with respect to said regimen set point.