Factors Influencing Water System Functionality in Nigeria and Tanzania: A Regression and Bayesian Network Analysis.

Sufficient, safe, and continuously available water services are important for human development and health yet many water systems in low- and middle-income countries are nonfunctional. Monitoring data were analyzed using regression and Bayesian networks (BNs) to explore factors influencing the functionality of 82 503 water systems in Nigeria and Tanzania. Functionality varied by system type. In Tanzania, Nira handpumps were more functional than Afridev and India Mark II handpumps. Higher functionality was associated with fee collection in Nigeria. In Tanzania, functionality was higher if fees were collected monthly rather than in response to system breakdown. Systems in Nigeria were more likely to be functional if they were used for both human and livestock consumption. In Tanzania, systems managed by private operators were more functional than community-managed systems. The BNs found strong dependencies between functionality and system type and administrative unit (e.g., district). The BNs predicted functionality increased from 68% to 89% in Nigeria and from 53% to 68% in Tanzania when best observed conditions were in place. Improvements to water system monitoring and analysis of monitoring data with different modeling techniques may be useful for identifying water service improvement opportunities and informing evidence-based decision-making for better management, policy, programming, and practice.