This work investigates the modeling and verification of seawater reverse osmosis powered by renewable energy resources (SWRO-RES). The model includes one stage of RO membranes, high pressure (HP) pump, energy recovery devices (ERD), Wind turbines (WT), photovoltaic panels (PV), and electrical grid as a back-up for the cases when there is weak penetration of the RES. Antibugging and tracing for the computer model were used as part of the code verification to discover all coding errors and check whether the computer model conforms to the SWRO specifications. After that, the calculations verifications process was performed using sensitivity analysis (SA) to evaluate whether the model response follows the anticipated direction and to check the model at some extreme conditions. Four SA cases were implemented to evaluate the SWRO-RES freshwater production, freshwater concentration, recovery rate, and specific energy consumption (SEC). Case 1 was the SA for different feed pressure values. In this case, it is important to find the pressure value that gives the lowest freshwater concentration. Case 2 was the SA for different feedwater temperature values. While case 3 was the SA for the feedwater concentration. In all these cases, the model shows a verified response and as anticipated. The last SA case was to study the effect of different numbers of WT and PV panels and evaluate the electrical grid share considering one year of operation for the SWRO-RES plant.