A method of obtaining approximate integral transforms of second-order partial differential equations with non-constant coefficients is discussed. The inverses of these transforms may be found using the appropriate standard inversion techniques. Finite and infinite Fourier transforms are discussed as particular cases. The application of these transforms to groundwater flow equations is discussed briefly via two examples. The potential advantages of this technique for application to numerical solution of flow equations and diffusion-dispersion equations are: (1) for each independent variable that can be transformed, a dimension that would otherwise need to be considered numerically is eliminated, thus making larger problems accessible to computer analysis; and (2) the solution can be generated at the spatial and temporal locations of interest only, thus effecting further efficiencies in modeling a given aquifer system.