Access to drinking water and sanitation is essential for health and well-being, yet major disparities remain, especially in data-scarce regions such as Africa. SDG 6 aims for universal access, but current monitoring relies on costly, infrequent, and spatially uneven surveys and censuses with long reporting delays. This study develops a scalable remote-sensing framework to estimate piped water and sewage system access at approximately 2.56 km resolution using Sentinel-2 imagery, Afrobarometer survey responses, 30 m population data, and DINO self-supervised Vision Transformer features. The best model achieves AUROC values of 91.54% for piped water and 93.24% for sewage access. Across 50 African countries, population-weighted estimates strongly align with WHO/UNICEF JMP statistics for piped water ($R^2 = 0.92$) and show meaningful agreement for sewage access ($R^2 = 0.72$). In countries without Afrobarometer coverage, MAEs are 9.5% and 10.7%, with estimates within 15% of JMP values for 121.4 million and 159.7 million people, respectively. A Nigeria case study across 767 Local Government Areas (LGAs) shows that the framework reveals fine-scale environmental inequality. The largest no-access burdens reach 1.155 million people for piped water and 1.452 million for sewage, 7.9 and 8.3 times the median LGA burden, while top-decile no-access thresholds of 0.805 and 0.952 indicate that deprivation is widespread. These findings show that DINO-based satellite models can complement household surveys with low-cost, spatially detailed evidence for SDG 6 monitoring, infrastructure targeting, and environmental equity assessment.

翻译：饮用水和卫生设施获取对健康与福祉至关重要，但在非洲等数据稀缺地区仍存在显著差距。SDG 6 旨在实现全民覆盖，但目前监测依赖于成本高昂、频次低、空间分布不均且报告延迟较长的调查与普查。本研究开发了一种可扩展的遥感框架，利用 Sentinel-2 影像、Afrobarometer 调查数据、30米空间分辨率人口数据及 DINO 自监督 Vision Transformer 特征，以约2.56千米分辨率估算管道供水和排污系统接入率。最优模型对管道供水和排污接入的 AUROC 值分别达到91.54%和93.24%。在50个非洲国家中，人口加权估算值与 WHO/UNICEF JMP 统计数据的管道供水指标高度吻合（$R^2 = 0.92$），排污接入指标也呈现显著一致性（$R^2 = 0.72$）。针对未覆盖 Afrobarometer 的国家，平均绝对误差（MAE）分别为9.5%和10.7%，对应1.214亿和1.597亿人口的估算值偏离 JMP 结果不超过15%。尼日利亚767个地方政府区（LGA）的案例研究表明，该框架揭示了精细尺度的环境不平等：管道供水和排污的最大未覆盖人口分别达115.5万和145.2万，为LGA中位数负担的7.9倍和8.3倍；而顶层十分位未覆盖阈值（0.805和0.952）表明剥夺现象广泛存在。这些发现表明，基于DINO的卫星模型能以低成本、高空间分辨率的证据补充入户调查，支撑SDG 6监测、基础设施精准配置及环境公平性评估。