Improving the productivity of rainfed agriculture needs the bridging of the dry spells. Water System Innovations are key to addressing food security and poverty alleviation. This book explain result of a study conducted in semi-arid areas of Pangani basin, north-eastern Tanzania, to understand the reasons for low adoption rates of water system innovations at smallholder farm level settings. The objective was to determine the conditions for sustainable adoption of smallholder water system innovations over time. The outputs are expected to contribute to higher uptake and adoption rates of the innovations. The study investigated critical determinants of adoption of the key water system innovations at farm- level and evaluated strategies, tools and approaches for promoting farmer-led innovation process. There are significant positive relationships between adoption and the household livelihoods assets implying that these are critical determinants of technology adoption at farm-level. Promotion of wider-scale adoption should match with appropriate technologies based on farm-level conditions, farmers' preferences, needs and objectives