Water quality modeling and distribution network evaluation in Hosanna Town, Ethiopia

• EPANET 2.2 used to model Hosanna Town water network with field validation • 3–12% of nodes had pressures outside recommended limits • Water age analysis identified stagnant zones in the network • Only 56% of nodes met WHO chlorine residual standards • Additional chlorination recommended to ensure safe water quality Ensuring safe and reliable drinking water remains a major challenge due to physical, chemical, and biological changes occurring within water distribution systems. In this context, the present study modeled and evaluated the water distribution network of Hosanna Town, Ethiopia, using EPANET 2.2 to analyze both hydraulic performance and water quality. To validate the model, laboratory results were systematically compared with simulated outputs for key parameters, including residual chlorine, turbidity, fluoride, nitrate, manganese, sulfate, electrical conductivity, phosphate, pH, copper, and iron, in relation to World Health Organization (WHO) and Ethiopian drinking water standards. The calibration results demonstrated excellent agreement between observed and simulated data, with an average absolute deviation of 0.714 and a correlation coefficient of 0.999. Following calibration, hydraulic analysis revealed that 5.67% of nodes failed to meet the minimum pressure requirement during peak demand periods, while 10.28% exceeded the upper pressure limit of 70 m. Conversely, during low-demand periods, 84% of nodes operated within the acceptable pressure range. In terms of water quality dynamics, water age was highest at 0.93% of nodes and lowest at 1.87% of nodes. Similarly, residual chlorine concentrations complied with WHO guidelines in 56.07% of nodes, whereas 9.35% of nodes showed no detectable chlorine. Based on these findings, the study recommends the installation of additional chlorination stations to maintain residual chlorine concentrations within the recommended range of 0.2–0.5 mg/L and thereby ensure the provision of safe drinking water.