Material and Method: The present study was performed in thirty-two first burst water samples and twenty-nine running tap water samples after two minutes, collected from an operation room at one standard hospital and analyzed for the mean, median, and 95% achieved confidence interval of CFU/ml. All water samples were cultured and investigated for total bacterial counts, which were expressed as colony forming unit per milliliter (CFU/ml).

Results: The bacterial count was statistically significantly about three times higher in the samples of the first burst tap water in comparison with the group of samples after letting the tap water run for two minutes 98.7, 78.5, 60.5-120.0 vs. 29.1, 25.8, 16.6-33.2 CFU/ml.

Conclusion: Two minutes running tap water contains about three times less bacterial count than first burst tap water.

Keywords: Tap water, First burst tap water, Running tap water, Bacterial count, Water contamination