During a rainstorm, rainwater seeps into the ground until the ground is saturated and the remaining water runs off into drains and ultimately streams and rivers. With the increase in impervious surfaces in cities, less water infiltrates during storms. The increase in runoff can overwhelm the storm sewer system and cause local flooding. Harvesting rainwater using a rain barrel reduces the harmful effects of runoff, and on-site use of captured rainwater reduces water treatment needs and reduces the use of potable water for residential uses.
Rain barrels are not difficult to install. Either cut a downspout to direct water through a screened opening on the top or install a diverter into a downspout that directs water through a tube to the barrel and allows overflow to continue through the downspout once the barrel is full. Make sure any openings are covered with screen to prevent mosquitoes from breeding in the water. You can even install a series of barrels, the next one filling when the previous one is full. A spigot near the bottom of the barrel allows you to fill a watering can or attach a hose. Placing the barrel on top of cement blocks or stand makes room for filling a watering can. This water should only be used for watering plants and is not safe for drinking without being treated first.
For more information, see this fact sheet.
Photo by Susan O'Donnell