Evaluation of tap water for surgical handwashing

In Japan, sterile water is used for rinsing in surgical handwashing, whereas in Western countries tap water is generally used. We conducted this study to examine the conditions and the equipment that affect bacterial contamination in tap water and to determine whether the tap water in our institute is suitable for surgical handwashing.

First, we examined the water pipes and measured the free chlorine content in the tap water in the operating room. Next, we recruited 40 volunteers and conducted preliminary tests with sterile water. Thirty of these subjects participated in a handwashing test using tap water.

The mean free chlorine levels in the tap water and the sterile water were 0.30 +/- 0.05 and 0.07 +/- 0.03 mg/l, respectively. The handwashing test using tap water showed immediate, persistent, and cumulative bacteria activity within the minimum limits set by the Food and Drug Administration (FDA).

The free chlorine levels in the tap water in our institute satisfied Japanese health regulations. Moreover, the handwashing test met the criteria of the FDA. Thus, we conclude that this tap water is safe to use for rinsing in surgical handwashing.