Like other regions around the world, southern Brazil has experienced periods of drought, having to find alternative water resources for producing drinking water during these times. The deep wells drilled in the Guarani Aquifer could help with this water imbalance, but the water, in some places, is brackish. This work is an exploratory study of the use of the brackish water from the Guarani Aquifer as an alternative supply for drinking water, using reverse osmosis to reduce the content of F-, SO42- and TDS (Total Dissolved Solids). The desalinated water obtained from reverse osmosis at a pressure of 2 MPa and a cross-flow velocity of 1.61 m.s(-1) showed rejections of approximately 94% for SO42-, 97% for TDS and 100% for F-. Blended water, produced by mixing groundwater and permeate, was proposed to optimize the produced drinking water with a recovery rate of 93%. Reverse osmosis is an excellent alternative for the supply of water in southern Brazil. (C) 2014 Elsevier B.V. All rights reserved.