<p>Persistent underperformance of rural water infrastructure in sub-Saharan Africa raises critical questions about its resilience under changing climatic conditions. While prior studies have identified climate variability as a potential risk factor, few have systematically quantified its influence, and even fewer the combined effects of climate and topography, on water access point (WAP) functionality at scale. This study analyzes 9,783 water access points across Zambia to assess how environmental variables, including mean annual precipitation (MAP), heavy rainfall (HR), and altitude (Alt), influence WAP functionality. Using logistic regression models stratified by elevation and a multivariate mixed-effects model with district and ward-level random effects, we disentangle both climatic and local contextual drivers of WAP performance. Findings reveal that environmental variables alone explain a modest 8% of the variation in functionality, while the inclusion of local context increases explanatory power to 35.4% and up to 49.3% when WAP type is factored in. Stratified models show that the effect of HR is elevation-dependent, positive at mid-altitudes (1000–1100&#xa0;m ASL), but negative at lower and higher elevations, thus suggesting a hydrological favourable topographic band for borehole reliability. Significant interaction terms (e.g., HR × Alt and MAP × HR) further highlight the complexity of climate impacts. While heavy rainfall events can enhance aquifer recharge, they may also undermine borehole reliability when interacting with vulnerable topographies. These findings highlight the importance of accounting for spatial heterogeneity and climatic interactions in the design of climate-resilient water infrastructure. The analysis also emphasizes the urgent need for investments in institutional, operational, and governance capacity, which remain critical yet underexplored determinants of long-term WAP functionality.</p>