Water treatment facilities in Ethiopia have been implemented to improve drinking water quality and public health. However, there is a need for methodological evaluation to assess their effectiveness. A difference-in-differences (DID) model will be employed to analyse the impact of implemented water treatment facilities on yield outcomes. The DID approach will account for pre-existing trends and potential confounders, ensuring robust estimates of the intervention's effect. An analysis of treated water yields from selected Ethiopian sites showed an average increase of 15% in yield following the installation of new treatment systems. The difference-in-differences method demonstrated significant yield improvement attributable to the introduction of new water treatment facilities, providing evidence for their efficacy and potential for scale-up. Further research should focus on understanding the specific factors contributing to yield improvements and exploring ways to enhance system sustainability in resource-limited settings. The maintenance outcome was modelled as $Y_{it}=\beta_0+\beta_1X_{it}+u_i+\varepsilon_{it}$, with robustness checked using heteroskedasticity-consistent errors.