Abstract: OBJECTIVE To continuously monitor the bacterial contamination of medical water in a hospital so as to provide bases for identification of risk points of the contamination and formulation of targeted countermeasures for control of health care-associated infections (HAIs). METHODS The water samples were regularly collected from stomatology department, central sterile supply department, bronchoscopy room and gastroenterology room by the infection control professionals. A multidisciplinary team collaborated to investigate and dispose the unqualified samples. Subsequently, management interventions were revised and implemented. RESULTS A total of 1561 water samples were monitored during 2020 to 2024, the average qualified rate was 96.80%, and the total qualified rate showed an upward trend (χ²= 17.621,P＜0.001). The qualified rate of the water for sterilization machines in the gastroenterology room was relatively low (78.31%) in 2020 and increased up to 100.00% after the interventions were implemented. The qualified rates of municipal water and water from storage tanks were higher than those of the water from water processing system (χ²= 4.739,P=0.029;χ²= 3.797,P=0.051). The water from sterilization machines of the bronchoscopy room exhibited the highest proportion of samples with zero colony-forming units (CFU/ml) (94.15%), whereas the water from sterilization machines of the gastroenterology room shows the highest proportion of samples with the bacterial colony counts exceeding 100 CFU/ml (3.53%). CONCLUSIONS It is an effective way to establish a closed-loop management mode based on continuous monitoring of data and achieve the efficient transition from passive disposal to active prevention and control of risks through multidisciplinary collaboration and information-based early-warning system so as to raise the qualified rate of medical water and provide propagable solutions for the medical institution.