Continual monitoring of access to water, sanitation and hygiene (WASH) is essential to get a clear picture of people’s needs and behaviour. Decision makers require evidence to inform their policies, plans and investments aimed at increasing WASH access, sustaining WASH access and bringing about progress towards the achievement of national and global goals. Service providers need regular up-to-date information to manage new and existing services – allocating resources and prioritising investment. Service users and civil society groups need this information to hold service providers to account and campaign for better access. Any agency involved in the delivery of WASH services – whether a private company, government body or an NGO like WaterAid – should be accountable for the quality and effectiveness of work that it does. For this reason, WaterAid also monitors its own performance and that of partners. We campaign for greater transparency in the funding and operation of the WASH sector to ensure money is spent and improvements made in the most effective way. We support monitoring and accountability at the global, national and sub-national and organisational levels to ensure improvements to water and sanitation services are sustainable and target those most in need.