The paper discusses problems of water engineering in the interwar period (1918-1939) in Poland, with a special focus on the work of Karol Pomianowski and Kazimierz Wóycicki. The name of Karol Pomianowski (1874-1948), professor of the Technical Universities in Warsaw, and after WW II, in Gdansk, is associated with all the major water-engineering projects of the interwar period. His last project, executed in a different form than that originally planned, involved designing a water-power plant at Bielany on the Vistula. Pomianowski had a very keen awareness of the shortcomings of Poland's water management before WW II, especially in face of the substantial needs of that period. While there were a lot of well-educated designers of water equipment and many efficient engineering firms, there was a significant shortage of funds. Trying to obtain loans from abroad was pointless, as major difficulties were involved in the servicing of credits. This meant that construction projects in the field took long years to complete, and the funding for them was continually reduced. Pomianowski saw a way out of the dilemma in accepting offers by the American company Harriman, which did not ask for guarantees, as well as by some Swiss firms. However, negotiations with those companies carried on for years and ended in 1932 with the offers being rejected. Kazimerz Wóycicki (1894-1944), a pupil of Pomianowski's, worked as his assistant and later, when he was already a professor of the Warsaw Technical University, as his closest collaborator on major design projects. Just as Pomianowski, Wóycicki could boast of a significant amount of research, although not all of it had been published before his untimely death from an artillery shell fragment during the Warsaw Rising of 1944.