With no doubt, sewer networks serve an essential element of any infrastructure system. They are buried in nature; as a result, their conditions are rarely triggered unless collapse situations occur. Nevertheless, some efforts have been accomplished in designing specific inspection cameras and sensors to help assessing sewer pipelines considering several sewer protocols. These protocols supply condition grades that suggest the overall conditions of the assets. Therefore, decision-makers can monitor the pipelines' states throughout their service lives. However, these conclusions encourage reactive maintenance, which results in significant costs and time when compared to proactive strategies. One method that could promote deploying the latter strategy is the deterioration modeling. These models are specially designed to predict the future conditions of any asset. Therefore, it assists practitioners in scheduling for inspection and deciding on the maintenance, rehabilitation or replacement (MRR) actions. As a result, the objective of this research is to design a dynamic deterioration model by employing the Weibull distribution analysis. The methodology shall propose three different deterioration curves: I) the ideal deterioration curve, which describes the ideal states of the pipelines' deterioration considering a specific service life; ii) the updated deterioration curve (UDC), which models the deterioration of the pipeline considering the condition after inspection; iii) the predicted deterioration curve (PDC), which models the deterioration of the pipeline after rehabilitation actions. This study is expected to provide informative conclusions for decision-makers when it comes to planning for inspection or MRR decisions for sewer pipelines.