HowLeaky is an open source water balance and water quality modeling environment. Its initial developed focused on assessing hydrology and water quality for a wide range of environments, land uses and management practices. This recent development integrates the model with dataset management and supports online simulation studies. This platform supports data archiving and sharing, Resources include access to climate data, soil hydrology and vegetation/soil management descriptors, nutrient and pesticide movement properties and data sets from field catchment and plot studies focusing on hydrology and water quality. The HowLeaky model operates at a point-scale using a daily time-step.