Water dispensers are popularly used in public areas and workplaces. Assessment of factors that affect the drinking water quality in water dispensers is important for the prevention of waterrelated diseases and other health risks. The aim of this study was to assess the bacteriological, physicochemical and sanitary parameters of drinking water in free water dispensers at Mahidol University, Thailand. Two models, namely, the bottled water dispensers (BWDs) and the bottle-less water dispensers (BLWDs), were used. The bacteriological results revealed a widespread of the coliform bacteria group in the BWDs while none were found in the BLWDs. Even so, the physicochemical results showed that 56.4% of the water samples from the BLWDs possessed the hardness value that exceeded the reference values of the drinking water regulation. For the assessment of the factors affecting drinking water quality, the number of faucets have an effect on the drinking water quality in the BWDs, of which the difference was statistically significant at p-value = 0.003 while the BLWDs have 3 factors that directly impacted the drinking water quality, namely, the location of water dispenser (p-value = 0.001), the drip tray water drainage system (pvalue = 0.026), and the pathogen source around the water dispenser (p-value = 0.022). Ultimately, the primary source of this problem may be due to a lack of routine maintenance and cleaning, some water dispensers could be considered unfit for use.