The city of Buffalo, like many cities along the Great Lakes, relies on a combined sewer network, which joins sewage effluent and stormwater. When the system is overwhelmed, excess water is discharged from outfall locations into local freshwater basins. To reduce unwanted discharge the City and community partners have invested in establishing rain gardens, to mitigate the stormwater volumes that enter the combined sewer network. Rain gardens offer a natural and aesthetically appealing space for surface runoff to enter, prior to runoff into the sewer network. Within the garden boundaries, the water may evapotranspire, naturally recharge into the groundwater, or pond on the surface. Using numerical modeling it is possible to quantify the benefits of these systems. The water balance is solved utilizes input parameters such as soil moisture and soil type using forward and inverse modeling approaches. This research highlights the applicability of modeling water movement through rain gardens in order to optimize stormwater storage. Additionally, different soil type specific parameters were passed through these models to indicate the influence of excess surface water entering gardens via surface runoff. HYDRUS-1D is less equipped for additional large volumes of water, which suggests a combination of groundwater and surface water models might be beneficial for future research efforts.