“I drink tap water as it is convenient and quick” – a mixed methods evaluation of water only school policies in London

Sugar sweetened beverages (SSBs) have been identified as a contributing factor to many non-communicable diseases. The London Mayor launched two Water Only Schools (WOS) toolkits aimed at primary and secondary schools (2021) to support their implementation in encouraging children to consume water in schools. A mixed-methods study using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework was conducted to evaluate the implementation and impacts of WOS in London. A survey was sent to 2212 schools to determine if they had a WOS policy. From these, 13 schools were selected for interviews with school staff, and surveys were administered to young people aged 9–14 and their parents. Quantitative and qualitative data were separately collected, analysed, and then merged and triangulated. There were positive attitudes towards the WOS policy among school staff, parents, and young people. In total, 324/566 schools (66.1%) reported having a WOS policy. Factors facilitating implementation included wider influences such as national and local policies, leadership and resources. Social media, home environment, and peer influence were found to impact young people’s behaviours. Schools faced barriers such as funding and resources and healthy school food provision. Adoption of WOS policy was more seamless in schools providing free school meals and thereby promoting healthy behaviours and tackling health inequalities.