First, it’s a question of increasing demand and decreasing supply.  Fresh water is actually a pretty scarce resource - only 1% of the water on earth is drinkable.  The global population is growing, and that means we need more water for irrigation to feed everyone, and water to drink and bathe in. 

You can painlessly save tens of thousands of gallons of water at home, with only habit changes and a few minor repairs.

Rain barrels attach to the end of your downspout and collect rain water, which can then be used to irrigate your lawn and garden.