en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <p><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Background:</strong> Safe drinking water is one of the main factors in improving health status of the population. The aim of this study was assessment of the microbiological quality, determination of pH and residual chlorine in water coolers&rsquo; drinking water in educational centers of Zanjan University of medical Sciences in 2015 and comparing the results with the Iranian national standards.</span></span></p> <p><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Methods: </strong>In this cross-sectional study, water samples of all used water cooler apparatuses were sampled and transferred rapidly to the laboratory. pH and residual free chlorine were measured by pH meter and&nbsp; Chlorine Residual Testing kit, respectively. Total coliforms, <em>Escherichia coli</em>, Mold and yeasts count were enumerated according to the Iranian national standards No. 1011, 3759, 5271 and 10899-1, respectively. Data were analyzed through the statistical softwares.</span></span></p> <p><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Results:</strong>The obtained results indicated that 44.44% of the samples were non-standard because of low residual chlorine. 44.44% and 27.8% of the taken water samples of water cooler dispensers were contaminated with mold or yeast and <em>Escherichia coli</em>, respectively.</span></span></p> <p><span style="font-size:14px;"><span style="font-family: times new roman;"><strong>Conclusion: </strong>According to some microbial contamination in water samples of water cooler devices to ensure availability clean water to consumers (students and hospital&rsquo;s visitors) continuous monitoring, proper maintenance and regular inspection of the water cooler dispensers seems necessary.</span></span></p> Microbial quality, Residual chlorine, PH, Water cooler, Water, Zanjan 105 111 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-47-2&slc_lang=en&sid=1 Samaneh Taghiloo samanetaghilou@yahoo.com 10031947532846009418 10031947532846009418 No Department Environmental Health Engineering Student Research center, Zanjan University of Medical Sciences, Zanjan, Iran. Hassan Hassanzadazar Hassanzadazar_h@zums.ac.ir 10031947532846009419 10031947532846009419 Yes Department of Food Safety and Hygiene, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Sajad Chamandoost sajadchamandoostt@yahoo.com 10031947532846009420 10031947532846009420 No Department of Food Safety and Hygiene, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Majid Aminzare majidaminzare@live.com 10031947532846009421 10031947532846009421 No Department of Food Safety and Hygiene, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.