Despite rapid economic growth in Asia, serious health, nutrition and development gaps persist, including inadequate services and inequitable access in the water, sanitation and hygiene (WASH) sector. We show that the WASH sector has ample justification for increased focus and investment to increase health and nutrition impact, but appropriate prioritisation and quality implementation of interventions are required to address these gaps. The Sustainable Development Goals present opportunities for an increased focus. We argue that the key components required to accelerate change include strengthened data availability, quality and use, institutional and policy reform for greater cross-sectoral integration and clear accountabilities at national and local level if countries are to achieve universal access with equity, sustainability and quality.