Iron corrosion and wastewater recovery are the most complicated and costly problems facing water utilities. A large number of parameters affect pipe corrosion, including water quality and composition. This work simulated reuse the reject water get out from reverse osmosis desalination plant as feed to cooling system. Evaluation of corrosion rate of pipeline that have been used in cooling system using this water after dosage of new corrosion inhibitors are studied by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The effect of temperature on the corrosion rate was investigated by the weight loss method and some thermodynamic parameters for corrosion. The results show that the inhibition efficiency increased with increase in inhibitor concentration and the results obtained from the techniques are in good agreement. The Langelier Saturation Index of the concentrate was reduced from 1.27 (High scale forming) to - 2.27 (No scale forming), thus treated water has properties of low fouling potential that facilitate its recycling and reuse in cooling system.