A rain barrel is a simple rainwater collector that is connected to the downspouts on your house. Instead of gutters sending water to the ground near your house or into the storm drainage system, the downspouts are connected to a large barrel that stores some of the runoff water from your roof for later use, such as watering your lawn, garden and potted plants.
Episode 10: "Waterwise Gardening" - King County Yard Talk. Make the most of every drop of water in your yard. This episode covers drought-tolerant landscaping, using cisterns and rain barrels and smart watering techniques.