People form their judgments of everyday phenomena based on multisensory information. This study investigates the relative impact of visual and auditory information on the perception of running tap water. Two visual and two auditory stimuli were combined to create four different combinations of high and low volumetric flow rate of tap water (the volume of water which passes through a faucet per time unit). Participants in each condition were asked to judge how long it would take to fill up a one-liter water bottle. The results demonstrate that the judgments were significantly influenced by visual and auditory information. Our data suggest that auditory information can play a significant role in everyday experience of running tap water even though participants are normally unaware of the effect of audition. These findings open the door to the idea of using auditory feedback of products in the context of proenvironmental behavior.