Research has shown that area of leak openings varies linearly with pressure under both elastic and viscoelastic conditions. However, hydraulic modelling of water distribution systems currently uses a power function that does not explicitly take into account leak area variation with pressure. This function is commonly known as the N1 power equation. This paper investigates the possibility of explicitly incorporating leak area variation into hydraulic modelling of water distribution systems. The FAVAD (Fixed And Variable Area Discharges) equation, which takes into account leak area variation with pressure, was incorporated into the widely used Global Gradient Algorithm (GGA) in EPANET. A stochastic model was developed to generate and distribute leaks in a standard water distribution system. It was based on existing theories about leakage in water distribution systems, taking into account physical properties of the system. Thereafter, hydraulic simulations were run using both FAVAD and N1 equations. The results show that the N1 power equation estimates the total system leakage with an error of up to 20%. On a specific junction, the leakage estimation error was found to be as high as 60%.