In situ rainwater harvesting (RWH) belong to the promising practices to support sustainable development in sub-Saharan Africa facing climate change impacts. However, appropriate indicators for their long-term sustainability are missing. Here, impacts for different aspects of sustainability are reviewed: in situ RWH practices improve hydrological indicators such as infiltration and groundwater recharge. Soil nutrients are enriched. Biomass production increases, with subsequent higher yields. Higher biomass supports a higher number of plants and animals, although native species might be replaced by crops as the landscape might change as a whole. This might strengthen conflicts between a nomadic and a sedentary population. Farmers applying in situ RWH practices profit from higher food security and higher income. However, some aspects are only poorly covered within the scientific literature. More integrative research concepts are needed.