The invention relates to a method for continuously treating water. According to this method, a constant dose of a chemically reactive substance is added to the raw water which flows into the process through a channel and is mixed in a flow. The resulting solution of the mixture is steadily guided further as the chemical reaction takes place and poorly soluble constituents are separated from the water. The treated water is continuously delivered for retreatment or use. The aim of the invention is to provide a simple means for producing water of a high quality in a small space. To this end, the inventive method is configured in such a way that the chemical substance is continuously metered into a directed, non-circulating, turbulent flow of raw water which leads into a mixing pipe and is then conveyed as a premixture into a spatially defined, delimited mixing area of a reaction vessel via the mixing pipe, said reaction vessel being configured as a mixing reactor. Part of the premixture is drawn into a floor area of the mixing reactor with a reduced cross section, re-mixed intensively in a chamber which is delimited by the reaction vessel and returned to the mixing area of the mixing reactor via a pressure pipe.