Reverse osmosis membranes are increasingly used in drinking water treatment. However, the production of a concentrate stream is the main disadvantage of its application. Increasing the recovery of the membranes in order to have the smallest amount of concentrate possible is an attractive approach. In the absence of bivalent cations in the feed water, silica and silica-derived precipitants are limiting factors in high-recovery reverse osmosis operations. The removal of silica in a separate pretreatment process might be the solution. Several methods were tested to remove silica. Precipitation of silica with Fe(OH)(3), Al(OH)(3) and silica gel was investigated, and also the removal of silica using a strongly basic anion (SBA) exchange resin.