Stenco designed and commissioned a Reverse Osmosis Plant for production water and feed to a steam boiler for a production of 50m3 / h. Water from a river with high alkalinity, hardness and salinity was not adequate for its production process. The plant consists of a pre-treatment with multilayer filtration, dosing of antifouling and reducer and microfiltration prior to osmosis membranes. At the exit of the Plant, a refining decalcifier has been installed to power the steam boiler. The water produced has a conductivity lower than 14uS / cm and <0.1ºF. The client has obtained an adequate quality for his productive process, obtaining at the same time important important energetic and economic savings with smaller consumption of water, fuel and purges of boilers.