Abstarct: When the negative pressure wave of water hammer reaches sensitive points such as leakage, it causes pollution to enter the pipe and endangers the health of society. Since the use of viscoelastic pipes has been increasing day by day, studies should be done for the effect of ram impact in this pipe and the volume of contamination. Therefore, in this research, an attempt has been made to investigate the effect of leakage and pressure in elastic and viscoelastic pipes by using laboratory data, and by obtaining the discharge coefficient, the leakage flow rate has been carefully calculated, and then the amount of the total volume of pollution has been calculated. In this research, the characteristic of method was used to model the unsteady flow and the Lagrangian method was used to model the contamination. The results show that the amount of pollution entering and the total volume of pollution is at a certain level of the pipe length and area and then it decreases. Also, by obtaining the leakage flow rate baxsed on numerical modeling and comparing it with the laboratory leakage flow rate, the numerical leakage flow rate is reduced by 6.28% compared to the laboratory leakage flow rate.