There are many ways in which people can be told not to waste water, but the Uji Shower Head could easily be one of the more effective approaches. It essentially shames people into taking shorter showers. By installing the Uji Shower Head in one's home, it will actively encourage people to be more aware of their water usage by turning different colors depending on how long they have been in the tub.
As Brett Andler states, "[The Uji Shower Head] encourages [people] to take shorter and more energy efficient showers. By letting people become aware of how long they're in the shower, we've actually been able to cut shower time by 12 percent." If that doesn't satisfy people, perhaps this stat will: Dvice reports that the shower head essentially pays for itself in seven months.