Shared sanitation in informal settlements: A systematic review and meta-analysis of prevalence, preferences, and quality

Shared sanitation facilities are not considered a type of basic sanitation by the WHO/UNICEF Joint Monitoring Programme (JMP), though they may be the only alternative to open defecation in urban informal settlements. Additionally, JMP indicators for sanitation do not cover aspects related to the quality of shared sanitation, such as those outlined in the Human Right to Water and Sanitation (HRTWS) framework. Data on the prevalence of shared sanitation within informal settlement areas is limited, and there is a need to understand user preferences, experiences, and barriers to the use of shared sanitation to inform effective policy and practice. This systematic review aims to summarize the prevalence and number of households sharing sanitation in informal settlements globally, as well as user experiences and barriers to successful implementation of shared sanitation. We included studies available in English and published after January 1, 2000. We retrieved 4741 articles from seven databases and included a total of 167 relevant publications. Among included studies, 54 reported the prevalence of shared sanitation in informal settlements, and 138 studies reported on user perceptions and experiences related to shared sanitation quality. A meta-analysis of studies reporting the prevalence of shared sanitation in informal settlements globally revealed an estimated overall prevalence of 67% [95% CI: 61%–73%]. Commonly reported user preferences included cleanliness to promote continued use of shared facilities, privacy with a lockable door, facilities for menstrual hygiene management, safety and protection against violence, 24/7 access, proper lighting, and shared responsibility for facility management — which align with the HRTWS framework and represent barriers to shared sanitation use. Based on the findings of this review, we recommend including the number of households or people sharing a sanitation facility in monitoring of shared sanitation quality, locating sanitation facilities within compounds, where applicable, and promoting safety, dignity, and privacy of all users in the development of shared sanitation quality indicators.