Abstract This paper describes the corrosion of equipment by high pH sour water in desulfurizing, MEA gas scrubbing and sour water stripping processes. The sour water is formed by the catalytic conversion of nitrogen and sulfur, present in vacuum gas oil, to ammonia and hydrogen sulfide. The ammonia and hydrogen sulfide dissolve in water condensed in the reactor effluent, MEA gas scrubbing and sour water stripping units to produce alkaline sour water. The materials corroded, rates of corrosion and factors which influence the corrosivity of sour water are discussed. The materials showing rapid corrosion have been carbon steel and copper base alloys which are required for salt water. The control of sour water corrosion has been achieved by upgrading equipment to titanium or high nickel alloys, inhibitor injection and changes in the process and mechanical design. Each of the corrosion processes described, alloy changes, design changes and the use of inhibitor has been based on, experience in other refineries, cost, fabricability, installation cost and its effect on the process. The mechanical service factor of the units is now > 90 percent compared with 70-75 percent in the first years of operation.