Rain Barrels are a great way to reduce the amount of runoff from your roof! Rain barrels are rainwater collection systems that connects to your downspouts to store rain water. The stored water is free soft water that can be used to wash cars, top off swimming pools, water gardens or lawns, window washing, etc.
Rain barrels are typically 55 gallons (but come in a variety of sizes). They can be bought at local gardening or retail stores, or made at home.