Drinking water quality in public healthcare facilities in Sindh, Pakistan: A cross-sectional assessment of microbial and physicochemical contaminants

Background: Access to safe drinking water is critical for patient care and infection prevention in healthcare facilities (HCFs). In Sindh, Pakistan, limited monitoring data exist despite widespread reports of contamination. Objective: The objectives of this study were to evaluate the physicochemical and microbiological quality of drinking water supplied to HCFs across Sindh and assess associated patient safety risks to inform infection prevention and control (IPC) strategies and guide water quality interventions. Methods: A total of 280 water samples were collected from 136 HCFs across 26 districts and analysed for key physicochemical parameters and microbial contamination indicators (total coliforms [TC], Escherichia coli [E. coli]). They were analysed following American Public Health Association standards. Data were interpreted against the World Health Organization (WHO) drinking water guidelines. Multi-variate facies and hydrochemical interpretation were applied to explain contamination sources and controls. Results: Contamination patterns were highly variable spatially, with groundwater sources contributing primarily to salinity, hardness and sodium exceedances, whereas surface water sources were associated with turbidity and microbial risks. Filtration plants demonstrated variable performance. District-level exceedances identified clear contamination hotspots that require targeted intervention rather than uniform policy responses. Total dissolved solids exceeded the WHO limits in 30% of samples, particularly in Naushero Feroze, Shikarpur, Sanghar, and Umerkot. Turbidity exceeded permissible values in 20.7% of samples, mainly in Thatta, Sujawal, and Sukkur. Chloride and hardness exceeded guideline limits in 22.1% and 16.1% samples, respectively, predominantly in groundwater. Sodium exceeded limits in 25% of samples. Fluoride and arsenic contamination remained localized. Microbiological contamination was widespread, with TC detected in 76.3% and E. coli in 18.6% of samples. Multi-variate analyses provided further insights; principal component analysis identified mineralization (PC1, 49.45%) and carbonate equilibrium (PC2, 10.63%) as key controls, while hydrochemical facies analysis distinguished precipitation-dominated Ca–Mg–HCO₃ waters, rock-dominated Na⁺ enrichment, and evaporation-driven Na⁺–Cl⁻–SO₄²⁻ salinization. Conclusion: A substantial proportion of drinking water in Sindh HCFs does not meet the WHO standards, presenting significant microbiological and chemical risks. Strengthened monitoring, effective disinfection, and water safety plans are urgently required to safeguard IPC and patient health in line with global IPC priorities and Sustainable Development Goal 6.