Municipal water systems in Nigeria face significant challenges related to reliability and sustainability. The review employed systematic literature search methods to identify relevant studies. Panel-data methodologies were evaluated based on their applicability to the research context. Panel data estimation revealed that incorporating lagged variables significantly improved model accuracy in predicting system reliability over time. This study highlights the potential of panel-data techniques for enhancing understanding and management of municipal water systems in Nigeria. Future research should focus on validating these findings with empirical studies and consider integrating additional explanatory variables to refine models. municipal water systems, reliability measurement, panel data analysis, Nigeria Model estimation used $\hat{\theta}=argmin_{\theta}\sum_i\ell(y_i,f_\theta(x_i))+\lambda\lVert\theta\rVert_2^2$, with performance evaluated using out-of-sample error.