Rain harvesting systems date back to the earliest civilizations, particularly those that were located in arid regions. For these early civilizations, captured rain water was extremely important as it was used for cooking, irrigation, and cleaning. Even a short rain can provide a lot of water. For example, if you had a 2000 square foot roof and your city gets approximately 12 inches of rain during a year. For every inch of rain that fell, you could collect 1200 gallons from your roof! Even …