Water scarcity slows down economical and industrial development, and population growth. Desalination by reverse osmosis is a separation process used to reduce the dissolved salt content of saline water to a usable level and offer one solution alternative to this problem. The use of simulators allows to obtain the optimal design in water production and energy consumption. The objective of this study was to select the operation conditions using the IMSDesign simulator, to provide a solution to water scarcity and satisfy the demand of population of Puerto Penasco, Mexico, with projection by the year 2040. Data entry, such as water quality, membrane modules, economic data and chemical costs were considered. Different membrane modules (SWC4-LD, SWC4-MAX, SWC5-MAX and SWC6-MAX) were tested in the design. Six different arrays were tested to each module. A design was considered optimal when the lowest energy consumption (kWh/m(3)), lowest investment cost ($USD/m(3)) and the highest elimination of contaminants (%) were obtained according to the concentration parameters (mg/L) established by the Mexican Norm (NOM-127-SSA1-1994) and the World Health Organization. The membrane module and array that complied with these conditions were SWC6-MAX with mixed permeate and energy recovery device. The results obtained were water permeate of $0.49 USD/m(3) and energy demand of 1.91 kWh/m(3). The simulation of a desalination process allows defining the operating condition and membrane type, at the same time, it reduces the operation and investment cost and increases the probability of solving water scarcity in Puerto Penasco.