Phenomena like urbanization and climate change will increase flooding problems, making it clear that more research and investments are needed in sewer systems to improve urban flood prevention. This research was done to determine factors influencing the sediment load to gully pots. It was assumed that in the measurement period, the retaining efficiency of the gully pots remains unchanged. Sediment levels in gully pots for a period of 3 months after cleaning were measured in the fall/winter period, in the cities of Rotterdam and The Hague. A probabilistic approach was used, consisting of a deterministic and random part. For the deterministic part, a generalized linear model is constructed to determine the influence of chosen parameters from the surrounding environment and the gully pot itself. For the random part, a normal distribution is used. The factors which were deemed to be relevant (p>0.05) are the tree factor (p=2,39E-06), inlet structure (p=2,05E-05), sand trap volume (p=9,52E-03) and road surface (p=1,28E-02). Parameters deemed not to be relevant are connected surface area (p=4,39E-01) and traffic intensity (p=3,33E-01). In further research, rainfall intensities should be included as well.