Partial blockages in pipes cause minor head losses that reduce the carrying capacity and increase operating costs due to energy consumption. The same effect - i.e., an undesirable minor head loss - can additionally be due to negligently partially closed in-line valves. Early detection of these singularities is of interest since prompt remedial actions have to be taken to keep on the requested performance level of the pipe. In the last decade, a number of promising transient test-based techniques were presented to detect blockages and to check the position and asset of in-line devices. Particularly for supply systems, these techniques are attractive for two main reasons: their very short duration and the possibility of using low cost pressure probes. This paper shows the first results of an extensive experimental campaign carried out at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy, on a long high-density polyethylene (HDPE) pipe system where the partial blockage is simulated by means of a smaller diameter HDPE pipe.