The rapid urbanization in Rwanda has led to increased demand for municipal water systems, necessitating robust assessment methods. A Bayesian hierarchical model will be employed to analyse data from various municipalities, incorporating spatial and temporal dependencies. This study provides a robust theoretical framework for assessing municipal water systems in Rwanda using advanced statistical methods. Future research should validate these findings through empirical studies and assess scalability of the model across different regions. The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.