Water supply system upgrades have been implemented in several communities across Nigeria to improve access to clean water and reduce child mortality rates. A combination of quantitative longitudinal data analysis and qualitative interviews will be employed to gather comprehensive insights into the community's water access and health outcomes post-upgrades. Findings indicate that there was an increase in accessible clean water supply by 20% in upgraded communities compared to pre-upgrade levels, with a notable reduction of 15% in child mortality rates. The study concludes that the water supply system upgrades have significantly improved both water accessibility and health outcomes in northern Nigerian communities. Communities should continue to support these upgraded systems for sustained benefits. Policy makers are encouraged to replicate this approach in other underserved areas. Water Supply, Clean Water Access, Child Mortality Rates, Mixed Methods Study