WaterAid and aid effectivenessAid effectiveness is about improving the quality of aid and its impact on development. In the water, sanitation and hygiene (WASH) sector, aid needs to strengthen the capacity of governments in developing countries to deliver sustainable services. If aid is not delivered effectively, it can hold back progress towards reaching everyone, everywhere with safe water, sanitation and hygiene. Development partners, national governments and civil society have agreed a set of principles for effective aid: Building local ownership, to create buy-in and sustainability. Harmonisation and alignment of external support behind country objectives and local systems, to reduce costs and help strengthen country processes so that they can deliver and sustain services in the long term. Improving joint monitoring and reporting of results, to ensure better-targeted interventions. Increasing mutual accountability and transparency in implementation, to increase legitimacy and reduce accountability distortions created by more traditional aid delivery mechanisms. But adoption of these principles has been slow, and assessments show that aid in the WASH sector is therefore not as effective as it should be. Improving the effectiveness of aid to the WASH sector is crucial to achieve our goal of universal access to clean water, sanitation and hygiene by 2030.