This paper investigates the potential of using controlled hydraulic transients for the non-intrusive internal condition assessment of water transmission pipelines. Deterioration of pipelines is a natural process. The effective tool for evaluating the state of the pipeline interior could be extremely useful while planning the rehabilitation or identifying critical points in the system. A non-intrusive technique for evaluating the state of internal surface of the pipeline is introduced. The total length of the pipeline is divided into a number of segments and the condition of each segment is assessed based on the transient response corresponding to that interval. In addition to quantification of the deterioration level of different sections of the pipeline, critical points were identified where closer investigation was suggested. The technique was tested on a real pipeline. The proposed methodology is in the early stage of development.