Water demand management: Visualising a public good.

Recent studies on water demand management show that providing visual information on water usage along with social comparisons with neighbouring households resulted in more efficient water usage. However, social comparisons can be discomforting for participants, especially in the case of downward or negative evaluations. To avoid this, some studies promote the use of social identity, a social norm approach that avoids comparisons. Past studies using social comparison used infographics, whereas other study types have used only textual (non-graphic) information. Therefore, in this study, we created a visualisation of water usage to highlight the importance of water as a shared resource, that is, as a public good, and feedback over six months according to the participants' water usage. A difference-in-difference analysis indicated that the feedback was marginally significant in decreasing water consumption immediately and continuously, especially for the middle and low use households, during the summer months, which is a period of perceived water shortage. From the questionnaire survey, we found that households felt that they determined their water usage based on their preference and were satisfied with the outcome.