AbstractThis article presents the history of the water supply system in Grudziądz (Poland) over the centuries, from the Middle Ages to the end of the nineteenth century. The location of Grudziądz on the high escarpment of the Vistula River made it difficult to supply water to the town. The innovative technical facilities, such as a water-work and water supply tower had to be constructed because the gravitational waterworks could not be applied. The basis for the research was the analysis of historical sources. In this study, non-invasive methods were used (aerial prospection, LiDAR scanning and geophysical surveys with Ground Penetrating Radar), since the hydrotechnical objects are located in a functioning urban space and no excavations could be carried out. The research included: (i) the measurements, exploration and preparation of photo-documentation of the water tower, (ii) providing a digital model of the tower, (iii) finding the tunnel inside the tower, and (iv) attempting to locate the tunnel's course outside the tower.