A water lead-through module is disclosed for discharging water into the sea through a hull of a marine vessel provided with a flow tube having a first end and a second end. The flow tube is of first grade steel, having an attachment flange part at the first end of the flow tube, and an outlet flange part at the second end of the flow tube extending radially outwards. A planar transition plate of a second grade steel has an outer periphery and includes an opening defining an inner periphery which conforms with an outer periphery of the outlet flange part, and wherein the transition plate is arranged axially flush with, rigidly connected to, by welding, the outlet flange part of the flow tube.