Assessment of Drinking Water Quality in the Public Network of Gadaref State, Sudan

Background: Access to safe drinking water remains a critical public health challenge in Sudan. This study assessed the bacteriological and physicochemical quality of water within the public distribution network of Gadaref Locality, Gadaref State, Sudan. Methods: An analytical cross-sectional study was conducted from January to November 2020. A total of 28 water samples were collected from the main storage tank, three sub-tanks, and household points across three distribution lines (Northern, Southern, Circular). Analyses were performed for Escherichia coli (E. coli), total coliforms, residual chlorine, and turbidity using standard field and laboratory methods (Pooltester, graduated turbidity tube, and membrane filtration). Supplementary data were gathered via interviews with water authority officials and field observations. Results: All samples from the main and sub-tanks were free of E. coli and total coliforms. Residual chlorine levels at these points were acceptable (0.3–0.4 mg/L). However, turbidity exceeded the WHO guideline value (5 NTU) in the main tank (7.5 NTU) and one sub-tank (6 NTU). At the household level, 41.7% (10/24) of sampled homes showed bacteriological contamination with E. coli (range: 1–18 CFU/100 ml), strongly associated with low or absent residual chlorine (0.0–0.2 mg/L). A statistically significant relationship was found between residual chlorine levels and E. coli contamination at household points (χ² = 11.93, df = 2, p = 0.003). Turbidity in household samples varied (2–7 NTU). Interviews confirmed a severe water scarcity issue, with the network covering only ~35% of the population, and revealed a breakdown in routine water quality monitoring. Conclusion: While water quality at the source was generally bacteriologically safe, significant secondary contamination occurs during distribution and storage at the household level, exacerbated by low residual chlorine. The study highlights a critical need for strengthened chlorination practices, infrastructure maintenance to reduce turbidity, expansion of the network coverage, rehabilitation of monitoring systems, and community health education on safe water handling.