Water, sanitation, and hygiene (WASH) interventions have been implemented in rural communities to reduce child mortality rates. In Ethiopia, these efforts are crucial given the country's high prevalence of waterborne diseases. A mixed-method approach combining quantitative data from health records with qualitative insights through interviews was employed. Data were collected over a two-year period in selected villages. Analysis of the data revealed that improved WASH infrastructure correlated with a significant decrease (p < 0.05) in child mortality rates by 20% across participating villages. The findings suggest that targeted WASH interventions can effectively contribute to reducing child mortality, highlighting the importance of continued and scaled-up efforts. Governments and non-governmental organizations should prioritise funding for WASH programmes in rural areas to ensure equitable access to basic hygiene services. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.