The objective of the present work is to monitor and control the physicochemical quality of the osmosis water that feeds the dairy industry in our case the Danone plant (DP) "Factory of Salé", for good production and use without no risk. The drilling water treatment and purification technique applied in the Danone plant is reverse osmosis. The approach of this membrane technique at a pressure gradient, allows obtaining good quality water for use in the various activities of the plant. During a 30-day period, we tested the pH, conductivity, alkalinity, hydrometric title, total alkalinity, chlorides content and chlorine content on water drawn from the borehole, the 1μ filter output, the treated output A and the treated water. The results of the experimental analyzes generally comply with the standards imposed within the plant, with the exception of a few days where cleaning of the membranes is necessary.