Process evaluation of an urban piped water supply infrastructure improvement programme in a cholera hotspot

Large-scale investments in water supply infrastructure will be required to achieve Sustainable Development Goal (SDG) 6. Safely managed water services are also a central element of global strategies to prevent cholera and diarrhoeal diseases. However, evidence remains scarce on how to efficiently improve piped water services in the complex settings that bear high disease burdens and where infrastructure investments are most needed. We conducted a process evaluation of a large-scale water supply infrastructure improvement programme in the town of Uvira, an endemic cholera hotspot in South Kivu, Democratic Republic of the Congo. Considering three evaluation domains – context, implementation of the intervention, and population response –, we assessed the validity of the programme’s theory of change and its underlying assumptions. Information sources included documents related to construction works and to the programme implementation, operational and billing records from the water system operator, and household surveys, covering the period from 2014 until 2021.The programme did not achieve the expected improvements in the water supply service available to the population of Uvira during the evaluation period. Contextual challenges included major events such as extreme flooding in early 2020 and the Covid-19 pandemic. Issues related to the electricity supply and the rise of Lake Tanganyika emphasise the need for cross-sectoral approaches and consideration of climate change in the planning of water supply infrastructure. Implementation challenges underlined a need for capacity strengthening alongside infrastructure improvements. Population response elements revealed the importance of designing affordable interventions and of taking informal practices such as the sharing of household taps into account. The programme was a good example of early engagement with researchers. Pragmatic evaluation approaches combining relevant methods should be adopted for the generation of useful scientific evidence from complex programmes in order to inform and enhance the effectiveness of future infrastructure investments contributing to progress towards SDG6.