In this report, we present a semiempirical method for determining water content of methane-rich hydrocarbon gas in equilibrium with gas hydrates. A model based on equality of fugacity concept for estimating the water content of methane in equilibrium with gas hydrates is first introduced. The model estimates the water content of methane using the vapor pressure of the empty hydrate lattice and the partial molar volume of water in the empty hydrate as well as pressure and temperature of the system. In order to extend the capabilities of this tool for determining water content of methane-rich hydrocarbon gases in equilibrium with gas hydrates, a correction factor, which is a function of gas gravity and the system pressure, is used. The predictions of the developed technique are found in acceptable agreement with independent experimental data (not used in developing this method) reported in the literature and the result of a previously reported predictive tool, demonstrating its reliability for estimating the water content of methane-rich hydrocarbon gas in equilibrium with gas hydrates.