Achieving water security remains an elusive goal yet the benefits of investing in water, sanitation and hygiene to achieve basic water security and alleviate poverty are clear. Households benefit through a range of livelihood impacts; economies benefit from greater economic activity and over the longer-term, households and economies benefit through greater resilience to climate change and shocks. So why are governments and their development partners struggling to meet water and sanitation targets? What factors make it difficult to sustain services at scale? And how can policies and plans for delivering and sustaining services for poor people be strengthened in the face of multiple pressures, including climate change? This book addresses these questions and draws conclusions for policy and practice, linking findings with current international debates on service delivery in rural areas. This book should be read by government agencies, donor organisations and NGOs, as well as academics and researchers in the water, sanitation and hygiene sector. Published in association with ODI.