For many people, SDG 6 is still synonymous with Water, Sanitation and Health (WASH), as in the Millennium Development Goals (MDGs). However, SDG 6 is much more than this; it covers the full water cycle, whereas the earlier MDGs included only WASH explicitly, and water scarcity implicitly through the water stress indicator. SDG 6 includes many important factors that influence environmental stability, water quality, sustainable water withdrawals, WUE, IWRM (which includes aspects of land management that affect water quality and quantity), protection for water- related ecosystems and the importance of participation and working together to make the best use of scarce resources.

This chapter offers a synthesis and critical review of SDG 6's eight targets. The targets comprise provision of drinking water (6.1), sanitation and hygiene services (6.2), treatment and reuse of wastewater and ambient water quality (6.3), WUE and scarcity (6.4), IWRM, including national and transboundary cooperation (6.5), protection and restoration of water- related ecosystems (6.6), international cooperation and capacity building (6.a) and local participation in water and sanitation management (6.b).

SDG 6 also includes 11 indicators that measure progress towards the targets. Some indicators are well developed and have already proved their usefulness, such as the WASH indicators, which have benefited from data sets established during the MDG period. However, many indicators are still in their infancy, lacking data and monitoring systems and aggregating to national and global levels. Some need further development. Also, few developing countries have the capacity to set up data monitoring, collection and analysis. Nevertheless, despite the teething problems, the indicators collectively represent the most straightforward and standard way to quantify a nation's water security and provide that balance between the many dimensions of water security and the need for simplicity and pragmatism (MacAlister et al. 2023). In 2015, the Integrated Monitoring Initiative for SDG 6 (IMI- SDG 6) instigated a programme to support countries in establishing baseline data, building national ownership, integrating and mainstreaming data collection and analysis and consolidating and sustaining the process.