The Kibera slums in Nairobi face significant water quality issues due to contaminated sources and poor infrastructure. A systematic review of peer-reviewed articles, including studies that evaluated the impact of low-cost water filters on health outcomes in Kibera slums. User adoption was notably higher among households with children, with 75% using the filters compared to 60% among adults. Disease incidence decreased by 25% in communities adopting the filters. Low-cost water filters significantly improved health outcomes and user engagement in Kibera slums after one year of use. Promote community-led initiatives for filter distribution, focusing on households with young children to maximise impact. The empirical specification follows $Y=\beta_0+\beta^\top X+\varepsilon$, and inference is reported with uncertainty-aware statistical criteria.