Recent evidence suggests that many improved drinking water supplies suffer from poor reliability. A new study [1] investigates what impact poor reliability may have on achieving health improvement targets. A Quantitative Microbiological Risk Assessment was conducted of the impact of interruptions in water supplies that forced people to revert to drinking raw water. Data from the literature were used to construct models on three waterborne pathogens common in Africa: Rotavirus, Cryptosporidium and Enterotoxigenic E. coli. Risk of infection by the target pathogens is substantially greater on days that people revert to raw water consumption. Over the course of a few days of raw water consumption, the annual health benefits attributed to consumption of water from an improved supply will be almost all lost. Furthermore, risk of illness on days drinking raw water will fall substantially on very young children who have the highest risk of death following infection. Agencies responsible for improving drinking water provision will not make meaningful contributions to targets if those systems are subject to poor reliability. Funders of water quality interventions in developing countries should put more effort into auditing whether interventions are sustainable and whether the health benefits are being achieved.

[1] Hunter, P.R., Zmirou-Navier, D. and Hartemann, P. (2009). Estimating the impact on health of poor reliability of drinking water interventions in developing countries. Science of the total environment ; vol. 407, no. 8 ; p. 2621-2624. doi:10.1016/j.scitotenv.2009.01.018

Contact: Prof. Paul R. Hunter, School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, UK; Paul.Hunter@uea.ac.uk

Tags: financing, water quality, water supply, water-related diseases