Rapid sand filtration is a widely used technology to remove suspended solids in drinking water and wastewater treatment plants. One of the challenges of the rapid sand filtration is to reliably predict the removal efficiency of suspended solids and pressure drop as a function of filtration time. In this study we put forward a novel CFD model to simultaneously predict the solids concentration in the effluent and hydraulic resistence build-up in rapid sand filters. The CFD model is assessed against lab scale filtration data at different filter media grain sizes and filtration velocities. Our results show an overall satisfactory agreement with the observations. Finally, we highlight the complexity and need for further work in developing general CFD models for rapid sand filtration.