Save Water: Put a plastic bottle in your toliet tank!
Take a 1 quart plastic bottle, fill it with water, and put it in toliet tank. Everytime someone flushes in your household, you are saving 1 quart in water. 4 quarts = 1 gallon. If your household flushes 10 times a day, you will save 912.5 gallons of water each year.