Assessment of the quality of drinking water in storage tanks and its implication on the safety of urban water supply in developing countries

Background: Water quality problems are one of the manifestations of poverty and most developing countries including Ethiopia suffering a lot of health problems associated with consumption of contaminated water. Although communities living in urban areas of Ethiopia have access to piped water supply, cross-contamination in the distribution system and unsafe storage are the major source of water borne diseases hence they are mostly overlooked by water professionals. Results: All water samples collected from drinking water storage tanks were positive for total coliforms and faecal coliforms. The result of this study showed that the drinking water was microbially contaminated in all sampling points. The level of microbial contamination increased from before entering the storage tank to after leaving the storage tank indicating that the presence of leakage in the distribution system and contamination at the storage tanks. The turbidity was found in the safe water quality range (2.1–2.9 NTU). Conclusion: The current study indicated that all water samples were bacteriologically contaminated and none of them met the WHO maximum permissible limit of drinking water quality. The unsafe piped-water supply was attributed to both leakage and contamination in the distribution system or unsafe storage. Thus, detail risk assessment should be conducted from treatment to distribution including storage and safe handling of water at the point of use in order to provide complete intervention strategies in tackling waterborne diseases.