Real water losses derived from water supply systems represent an important topic, nowadays. It is difficult to predict and to calculate the water lost volume, these values being crucial in any water balance. In addition, the leakage flow can be estimated only when the geometric and hydraulic characteristics of the pipes and the period of time associated to the leakage are known. Also, by using the equation of the water flow can be obtained inaccurate values, especially when incorrect values of discharge coefficient are used. The values of the discharge coefficient can vary between 0.6 and 0.85, depending on a multiple aspects, such as the pipe diameter, the orifice size and shape, the pipe material, the orifice position on the pipe wall, the pipe thickness and the hydraulic parameters of the water (flow and pressure). This paper is focused of an experimental study of a leak simulation in a PVC pipe. Thereby, a circular orifice is drilled on PVC pipe wall and the influence of the water flow and pressure on the discharge coefficient (Cd) is analysed. The experimental values obtained for de Cd are 0.59 - 0.86, values that are in accordance with the results from similar studies.