Water bottles or tap water? A descriptive-social-norm based intervention to increase a pro-environmental behavior in a restaurant

The impact of humanity’s behavior on the ecological environment is a hot topic that has been widely studied over the past few years. The consumption of plastic bottled water has steadily increased, even in countries where the quality of tap water is considered excellent. This poses a problem for the environment for multiple reasons, for example: emissions due to transportation and non-biodegradable plastic waste. This paper addresses the issue of how policy-makers implement interventions aimed at increasing the consumption of tap water instead of bottled water. Specifically, it investigates how the use of a descriptive social norm in a restaurant might reduce the plastic bottled water consumption. Results show that the presence of the message “TWO IN THREE PEOPLE FROM THIS AREA DRINK TAP WATER” induced a significant impact on behavior because it decreased plastic bottled water sales by 12 percentage points, from 96% to 84%, considering only the 4055 water requests, bottled or tap, and not the overall number of drink orders. Behavioral public policy is discussed to discourage bottled water consumption.