Geotextile filters are currently under consideration as a potential treatment method for removing suspended solids from urban stormwater runoff. One important aspect of assessing the viability of a new filter is the duration in which it will function before becoming clogged. Predicting the hydraulic conductivity of the filter throughout the filter lifespan is one way in which the duration of use can be determined. In this study, a semi-theoretical model was developed which predicts the hydraulic conductivity of the filter system as a function of the mass of solids captured by the geotextile. Values for several parameters of the theoretical model were empirically derived using laboratory data. Using these values, the parameters were analyzed as functions of specific characteristics of the geotextile filters and the simulated stormwater containing the targeted suspended solids.