According to the results of the studies the reason of the worsening of water quality in the ozonizer [correction of ozonating] installations of household water supply of ships is the presence of negative biological processes in the system of household and drinking water in combination with the peculiarities of its operation and reliability of functioning of the ship ozonizer [correction of ozonating] station. New technological designs and automated control methods, maintaining the residual ozone doses in the ship network, are needed to keep the drinking quality of water in the system.