Rural drainage systems are often large and complex systems, which are difficult to model. In this work, a physical model based on the hydrology and hydraulic laws and a data-driven modeling approach with an ARX structure are created for the rural drainage system in Eiderstedt, Germany. Thereupon, the prediction accuracy for real measurement data of both models is investigated and the respective advantages and disadvantages are discussed. It is shown that both models are able to predict the water level quite well, with the physical and data-based model being more accurate for long- and short-term predictions, respectively.