Rainwater harvesting is an innovative alternative water supply that anyone can use and it also captures, diverts, and stores rainwater for the future.
Implementing rainwater harvesting is beneficial because it reduces water supply, and reduces run-off, erosion, and contamination of surface water.
Rainwater can be used for nearly any purpose that requires water. These include landscape use, storm water control, wildlife and livestock watering, in-home use, and fire protection. Please see the attached link and it will guide you to a calculator