An experimental study was undertaking over 12 months in a two-stage reverse osmosis module in the beverage industry. The groundwater was treated by reverse osmosis to eliminate the water solutes. The obtained results showed that the reverse osmosis process is well adapted for this treatment; the retention is more than 95% for the totality of solutes (the total conductivity decreased from 1070 mu s/cm to 33 mu s/cm). However, we observed fouling phenomena expressed in a decrease in the permeate flow. In addition, the mass balance carried out showed that the fouling principal factor is limestone scale on the membrane surface. The fouling evolution with time was modelled and presented by the R/R-m ratio variation.