A modest estimate of the average water usage for one shower is 25 gallons (five gallons per minute for a five-minute shower). Multiply this by 365 showers per year, and you’ve got roughly 9,125 gallons of water, per person, dedicated to showering annually. Now, let’s say in the United States only two-thirds of the population (204.6 million people) have the means to shower this frequently for this long. Annual U.S. water usage then, just for showers, comes to 1.8 trillion gallons of treated water that could be used for drinking water.
Now, if teenagers are showering, the numbers go up exponentially. Exactly, what are they doing in there anyway???